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GNDU Queson Paper 2022

BCA 1

Semester

PAPER-I: INTRODUCTION TO PROGRAMMING-C

Time Allowed: 3 Hours Maximum Marks: 75

Note: Aempt Five quesons in all, selecng at least One queson from each secon. The

Fih queson may be aempted from any Secon. All quesons carry equal marks

SECTION-A

1. (a) Why C is called middle level language?

(b) What is keyword? List various keywords of C. Write the use of any ve keywords.

2. (a) Explain data types of C.

(b) Which are unformaed Input funcorls?

SECTION-B

3. Compare the following statements of C. Also give an example of each:

(a) while and for

(b) break and connue.

4. Write a program to check if a number given by user is Palindrome or not.

SECTION-C

5. (a) What is a string? Explain any ve string manipulaon funcons.

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(b) Write a program to get a string from user and count number of vowels in it.

6. What is Recursion? Write a program to nd factorial of a given number using recursive

funcon.

SECTION-D

7. What is structure in C? Which are types of structures ? Explain the uses of structures:

Give an example.

8. What is a pointer ? How are pointers helpful in accessing an array ? Explain

call by reference.

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GNDU Answer Paper 2022

BCA 1

Semester

PAPER-I: INTRODUCTION TO PROGRAMMING-C

Time Allowed: 3 Hours Maximum Marks: 75

Note: Aempt Five quesons in all, selecng at least One queson from each secon. The

Fih queson may be aempted from any Secon. All quesons carry equal marks

SECTION-A

1. (a) Why C is called middle level language?

(b) What is keyword? List various keywords of C. Write the use of any ve keywords.

Ans: 1(a). Why C is called a Middle-Level Language?

Let’s begin this explanaon with a short, thoughul story.

󹴮󹴯󹴰󹴱󹴲󹴳 The Tale of the Bridge Builder

Once upon a me, in a vast kingdom of computers, there were two groups of languages —

one that spoke the language of humans (like English) and another that whispered in machine

code (just 0s and 1s). These two groups lived far apart, and they couldn’t understand each

other.

Now, many programmers lived in this kingdom. Some liked the human languages (called

high-level languages) because they were easy to use. Others preferred the machine

languages (called low-level languages) because they oered full control over the computer.

But this gap caused problems — the programmers couldn’t easily control the machine

without learning complex binary, and machines couldn’t understand English-like instrucons

directly.

Then came a young and brilliant builder — the C language. It built a bridge between the two

lands. It could talk to both humans and machines! It was powerful like machine language,

and also readable like high-level language.

And that’s how C became the middle-level language, standing right between high-level and

low-level languages.

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󷃆󼽢 Now, Let’s Understand This Technically:

C is called a middle-level programming language because it combines the best features of

both high-level and low-level languages.

Let’s break this down further:

󹻂 High-Level Language Features of C:

These are user-friendly and help the programmer write programs that are easy to read,

write, and understand.

• C supports structured programming (using funcons).

• It allows use of control statements like if, for, while.

• It supports data types like int, oat, char.

• You can write portable code, i.e., the same program can run on dierent computers

with lile or no modicaon.

󹻂 Low-Level Language Features of C:

These are close to machine-level instrucons and provide more control over the hardware.

• It allows direct memory access using pointers.

• You can write system-level programs like operang systems and device drivers in C.

• It supports bitwise operaons, memory management, etc.

󹻂 Hence, C is "Middle-Level":

Because it gives the power of low-level programming and the ease of high-level

programming — all in one language.

Examples of What You Can Do with C:

Feature

Example Use

High-level: Funcons

int sum(int a, int b) { return a + b; }

Low-level: Pointers

int *ptr = &num;

High-level: Loops

for (int i = 0; i < 10; i++)

Low-level: Memory management

malloc(), free()

Mixed: Bitwise operaons

a = a & b;

󹰤󹰥󹰦󹰧󹰨 Summary (1a):

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C is called a middle-level language because:

• It provides the eciency and control of low-level languages (like assembly),

• As well as the simplicity and structure of high-level languages (like Python, Java),

• Thus, it acts as a bridge between machine and human-readable code.

1(b). What is a Keyword?

List various keywords of C.

Write the use of any ve keywords.

󽄡󽄢󽄣󽄤󽄥󽄦 Denion: What is a Keyword?

In simple terms:

A keyword is a special word that has a xed meaning in the C language and cannot be used

for anything else like variable names.

They are the building blocks of C programs.

Think of them as the grammar rules of the language. Just like in English, we can’t change the

meaning of “if” or “but”, in C, we can’t change the meaning of keywords like if, return, or

while.

󼪺󼪻 How Many Keywords Are There in C?

C language has 32 standard keywords (in tradional ANSI C). Some compilers add more, but

the core set is 32.

Here is the full list:

auto break case char const connue

default do double else enum extern

oat for goto if int long

struct switch typedef union unsigned void

volale while

󷗭󷗨󷗩󷗪󷗫󷗬 Usage of Any Five Keywords (with examples):

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Let’s now explore 5 important keywords and their uses:

1. int

󷃆󼽢 Use:

int is used to declare variables that store integer (whole number) values.

󼨽󼨾󼨿󼩁󼩀 Example:

int age = 25;

This means: "Create a variable called age which can hold integer values."

2. if

󷃆󼽢 Use:

if is used to make decisions in a program. It executes a block of code only if a certain

condion is true.

󼨽󼨾󼨿󼩁󼩀 Example:

if (age > 18) {

prin("You are eligible to vote.");

}

This will print the message only if the value of age is greater than 18.

3. return

󷃆󼽢 Use:

return is used to return a value from a funcon to the calling funcon.

󼨽󼨾󼨿󼩁󼩀 Example:

int add(int a, int b) {

return a + b;

}

This funcon returns the sum of a and b.

4. while

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󷃆󼽢 Use:

while is used to create a loop that connues to run as long as the condion is true.

󼨽󼨾󼨿󼩁󼩀 Example:

int i = 0;

while (i < 5) {

prin("%d\n", i);

i++;

}

This will print numbers from 0 to 4.

5. struct

󷃆󼽢 Use:

struct is used to group dierent types of variables into a single unit. It is like creang a

custom data type.

󼨽󼨾󼨿󼩁󼩀 Example:

struct Person {

char name[50];

int age;

};

Here, Person is a structure containing a name and age.

󷗛󷗜 Bonus Analogy – A Mini Story for Understanding Keywords:

Let’s imagine C language is a courtroom.

• The judge is the C compiler.

• Keywords are the laws of the court.

• You (the programmer) must follow these laws.

• You cannot redene or ignore these laws.

• If you try to make your own rule, like int if = 10;, the judge will immediately shout,

“Syntax Error!”

So remember: keywords are sacred in C — they tell the compiler exactly what to do.

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󼨐󼨑󼨒 Final Summary of Part (b):

Keyword

Purpose

int

Declares an integer variable

Used for condional branching

return

Sends a value from a funcon

while

Used for looping while a condion is true

struct

Groups dierent variables into one user-dened type

󹱑󹱒 Important Points:

• There are 32 reserved keywords in C.

• You cannot use keywords as variable names.

• Keywords are case-sensive: If, IF, and if are dierent (only if is valid).

󺚽󺚾󺛂󺛃󺚿󺛀󺛁 Conclusion:

Understanding why C is called a middle-level language gives you a deep appreciaon of its

power — it's the language that blends the machine's logic with the programmer's thoughts.

Learning about keywords helps you use the language properly and eecvely, like knowing

which keys unlock which doors.

By mastering both these concepts, you're not just learning to code — you're learning to

speak to the computer in its own voice.

2. (a) Explain data types of C.

(b) Which are unformaed Input funcorls?

Ans: (a). Once upon a me in a digital kingdom, there lived a wise old compiler who

managed a land full of numbers, characters, and informaon. Every piece of data in the

kingdom had to belong to a specic group so the compiler could manage memory and

operaons eciently. This magical grouping was known as Data Types in the world of C

programming.

Let us now take a guided journey through this data kingdom to understand how each type

works, where it lives, and why it is important.

󷫋󷫌󷫍󷫎󷫏 What Are Data Types in C?

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Think of data types like labels or containers. In real life, we store water in boles, books on

shelves, and money in wallets — each item has a specic type of container. Similarly, in C

programming, data types dene what kind of data we are storing and how much space it

needs in memory.

Without data types, the computer would be confused — it wouldn’t know whether to treat

a number like an integer, a decimal, a character, or something else.

󹵲󹵳󹵴󹵵󹵶󹵷 Major Categories of Data Types in C

In C, data types are primarily divided into four broad categories:

1. Basic Data Types

2. Derived Data Types

3. Enumeraon Data Types

4. User-Dened Data Types

Let’s now explore each category with relatable examples.

1. 󼩕󼩖󼩗󼩘󼩙󼩚 Basic Data Types

These are the foundaon stones of the C language. They include:

a) int (Integer)

This type is used to store whole numbers — like 1, 2, 100, -5, etc.

• Example: int age = 25;

• Size: Usually 4 bytes

• Range: -2,147,483,648 to 2,147,483,647 (on most systems)

The int type is like a locker that only stores whole things — no fracons allowed!

b) oat (Floang Point)

Used for storing decimal values like 2.5, 3.1415, -0.99, etc.

• Example: oat price = 99.99;

• Size: 4 bytes

• Precision: Up to 6 digits aer the decimal

You can think of a oat like a weighing scale — it’s perfect when precision maers but

doesn’t need to be exact.

c) double (Double Precision Floang Point)

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When oat is not enough, double steps in.

• Example: double pi = 3.14159265359;

• Size: 8 bytes

• Precision: Up to 15 digits aer the decimal

It’s like a scienc calculator — more space and more accuracy.

d) char (Character)

This stores a single character like 'A', 'b', '#', '9', etc.

• Example: char grade = 'A';

• Size: 1 byte

Behind the scenes, char uses ASCII values. For example, 'A' is stored as 65.

󷉃󷉄 Story Time: The Tale of the Mismatched Variable

Once, a young programmer named Riya was building a calculator in C. She wrote:

int result = 5.5;

But when she printed the result, it was just 5!

The compiler whispered, "You asked me to store a decimal number in an integer box — so I

chopped o the decimal!"

Moral of the story? Always choose the right data type to avoid surprises!

2. 󼨻󼨼 Derived Data Types

These are created using basic data types. They include:

a) Array

A collecon of elements of the same type.

• Example: int marks[5] = {90, 85, 78, 92, 88};

Think of an array as a row of mailboxes, each holding a value of the same type.

b) Pointer

Stores the memory address of another variable.

• Example: int *ptr = &age;

Pointers are like GPS trackers — they don’t hold the data but show where the data lives.

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c) Funcon

In C, funcons are also considered derived data types because they work with data types as

return types and arguments.

3. 󼩕󼩖󼩗󼩘󼩙󼩚 Enumeraon Data Types (enum)

These are user-dened types consisng of named integer constants. They make the code

More readable for xed number of

iteraons

󷇴󷇵󷇶󷇷󷇸󷇹 Real-Life Analogy

Think of while loop as checking your wallet before buying something — you’ll only proceed if

you have enough money.

while(money >= price) {

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buy_item();

money -= price;

}

Think of for loop as going to the gym and deciding to do 10 push-ups — you already know

how many mes to do it.

for(int i = 1; i <= 10; i++) {

do_pushup();

}

󹴷󹴺󹴸󹴹󹴻󹴼󹴽󹴾󹴿󹵀󹵁󹵂 Short Story: The Sandwich Shop

Anu wanted to make sandwiches unl she ran out of bread. So she used a while loop.

int bread = 5;

while(bread > 0) {

prin("Made a sandwich.\n");

bread--;

}

Rahul, on the other hand, wanted to make exactly 5 sandwiches no maer what.

for(int i = 0; i < 5; i++) {

prin("Made a sandwich.\n");

}

Both made sandwiches, but the mindset was dierent!

󼨐󼨑󼨒 PART B: Comparing break and connue in C

󺪸󺪹 1. What is break?

The break statement is used to immediately exit the loop or switch block.

When break is executed, the loop stops and the control jumps outside the loop.

󷋣󷋤 Example of break:

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#include <stdio.h>

int main() {

for(int i = 1; i <= 10; i++) {

if(i == 6) {

break;

}

prin("%d ", i);

}

return 0;

}

󹴮󹴯󹴰󹴱󹴲󹴳 Output:

1 2 3 4 5

󷗭󷗨󷗩󷗪󷗫󷗬

Explanaon:

• The loop stops as soon as i becomes 6.

• It doesn’t complete all 10 iteraons.

󷃆󼼐 2. What is connue?

The connue statement skips the current iteraon and goes to the next one.

It does not exit the loop enrely.

󻐜󻐝󻐞󻐟󻐠󻐡󻐢󻐣󻐤󻐥󻐦󻐧󻐨 Example of connue:

#include <stdio.h>

int main() {

for(int i = 1; i <= 10; i++) {

if(i == 6) {

connue;

}

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prin("%d ", i);

}

return 0;

}

󹴮󹴯󹴰󹴱󹴲󹴳 Output:

1 2 3 4 5 7 8 9 10

󷗭󷗨󷗩󷗪󷗫󷗬 Explanaon:

• When i becomes 6, it skips the prin and moves to 7.

• The rest of the loop connues normally.

󹸯󹸭󹸮 3. Comparison Between break and connue

Feature

break

connue

Funcon

Exits the loop enrely

Skips the current iteraon

Eect on

Loop

Control jumps outside the loop

Control jumps to the next loop cycle

Common

Use

When a condion is met to stop

completely

When a specic condion should be

ignored

Placement

Usually inside if statements

󷇴󷇵󷇶󷇷󷇸󷇹 Real-Life Analogy

Imagine a movie theatre.

• If there's a re alarm, everyone leaves immediately — this is like break.

• If someone’s phone rings, they just mute it and connue watching — this is like

connue.

󷻟󷻠󷻡󷻢󻯗󼊺󼊻󻯘󷻭󻯙󻯚󻯛󻯜󼊼󼊽󼊾󼊿󼋀󻯝󻯞󷻮󷻯󷻰󼋁󼋂󼋃󼋄󷻱󷻲󷻳󷻴 Short Story: Cooking Pasta

Anu is boiling pasta for dinner.

• If she nds the gas cylinder is empty, she stops cooking immediately — break.

while(true) {

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if(gasEmpty()) {

break;

}

cookPasta();

}

• If she sees one pasta is undercooked, she skips that one and connues boiling the

rest — connue.

for(int i = 0; i < 10; i++) {

if(pasta[i] == "undercooked") {

connue;

}

eatPasta(pasta[i]);

}

󷃆󼽢 Final Summary Table

Feature

while Loop

for Loop

break

connue

Usage

Type

Unknown iteraons

Known

iteraons

Exit the loop

Skip current

iteraon

Control

Flow

Entry-controlled

Entry-

controlled

Jumps outside

the loop

Jumps to next

iteraon

Flexibility

High, but requires

manual updates

Compact and

structured

Used for early

exit

Used to skip

some condions

Example

Use

Wait for user input

Print 1 to 10

numbers

Stop loop when

error occurs

Ignore invalid

data in loop

󹰤󹰥󹰦󹰧󹰨 Pro Tips for Programmers

• Use for when you know how many mes you want to loop.

• Use while when you don’t know how long the loop should run.

• Use break to escape from a loop when something crical happens.

• Use connue to skip something without aecng the rest of the loop.

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󷓠󷓡󷓢󷓣󷓤󷓥󷓨󷓩󷓪󷓫󷓦󷓧󷓬 Conclusion

Just like Anu and Rahul, every programmer must choose their tools wisely. The while and for

loops are like two paths leading to the same desnaon — they both help us repeat code.

Similarly, break and connue give us powerful control over our loops, helping us make smart

decisions inside them.

By understanding the subtle dierences and praccing them with real examples, anyone can

master these fundamental concepts of C.

4. Write a program to check if a number given by user is Palindrome or not.

Ans: Imagine you're holding a magical mirror. This mirror doesn’t show your reecon;

instead, it ips numbers. Show it 121, and it reects back 121. Show it 123, and it returns

321. Now, here's the twist — if a number and its reecon in this mirror are the same, it’s a

Palindrome!

In simpler words, a palindrome number is one that remains the same when its digits are

reversed. Examples include 121, 1331, 44444 — these numbers are like calm lakes, sll and

symmetrical from both ends.

Now, let’s take this idea from the imaginaon world and bring it to life through

programming.

󼨐󼨑󼨒 Before the Code – Understand the Logic

A number is a palindrome if:

Its reverse is equal to the original number.

So, our task is:

1. Take a number from the user.

2. Reverse the digits of the number.

3. Compare the reversed number to the original number.

4. If both are the same, it’s a palindrome. Otherwise, it’s not.

Let’s now understand this concept using a short and simple story — just like you'd tell a child

while explaining a math problem.

󼬰󼬮󼬯 Short Story: The Kingdom of Numbers

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Long ago in the Kingdom of Numbers, King Palindro ruled with symmetry and order. His rule

was simple: "Only those numbers that look the same from front and back shall enter the

Royal Palace." One day, a curious number, 12321, knocked at the palace gates.

"Let me in!" cried 12321.

The gatekeeper reversed the number — starng from the end, reading it as 1-2-3-2-1 — and

found it to be exactly the same.

"You may enter!" said the gatekeeper with a smile.

Another number, 12345, tried to enter, but its reversed form was 54321 — not the same.

"Sorry, your reecon does not match. You cannot enter," replied the gatekeeper.

Thus, the rule of palindrome kept the kingdom perfectly balanced and beauful.

󹰤󹰥󹰦󹰧󹰨 How Do We Write a Program to Do This?

Let’s take this beauful concept and turn it into a working Python program.

# Palindrome Number Checker Program

# Step 1: Ask the user to input a number

num = int(input("Enter a number: "))

# Step 2: Store the original number

original_num = num

# Step 3: Reverse the number

reversed_num = 0

while num > 0:

digit = num % 10 # Extract the last digit

reversed_num = reversed_num * 10 + digit # Append the digit

num = num // 10 # Remove the last digit

# Step 4: Check if the original and reversed numbers are the same

if original_num == reversed_num:

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print("Yes! It is a Palindrome number.")

else:

print("No! It is not a Palindrome number.")

󹸯󹸭󹸮 Let's Break It Down Like a Detecve

Take the input 121:

• First digit (from the end): 1

• Next: 2

• Next: 1

We build the reversed number as:

• Start with 0 → 0 * 10 + 1 = 1

• 1 * 10 + 2 = 12

• 12 * 10 + 1 = 121

And voila! We get back the original number — hence, Palindrome!

󹴡󹴵󹴣󹴤 Another Short Real-Life Example

Think about a school quiz. You are asked: “Can you think of numbers that read the same

forward and backward?”

You smile and say: "Yes! 121, 909, 1221..."

Now think: wouldn’t it be amazing if your computer could do this too? That’s what our lile

Python code is doing — becoming your intelligent assistant in the world of numbers.

󷃆󹸊󹸋 Quick Glance at the Steps Again

Step

What Happens

Take user input

Store the original number

Reverse the digits using a loop

Compare reversed number with original

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Step

What Happens

Print the result based on comparison

󷕘󷕙󷕚 Why This is More Than Just a Program

Checking for a palindrome teaches us:

• How to manipulate numbers

• How to use loops and condions

• How to break problems into simple steps

It’s like teaching your computer how to “look in the mirror” — a fantasc introducon to

logical thinking!

󺫦󺫤󺫥󺫧 Want to Try a Shorter Version Using Python Tricks?

Here’s a one-liner magic trick using Python:

num = input("Enter a number: ")

print("Palindrome!" if num == num[::-1] else "Not a Palindrome!")

Here, num[::-1] ips the string. But remember, this works only because we treat the number

as a string.

󷙎󷙐󷙏 Conclusion

So, in the magical world of programming, palindrome numbers are like royal guests who can

look the same in both direcons. With just a few lines of code, we’ve made a mirror that

reects any number and checks if it’s worthy of entering King Palindro’s palace!

Whether it’s 121, 4444, or even 99999, you now know how to spot a palindrome — and

more importantly, how to teach your computer to spot it too!

And that’s the real beauty of learning to code — turning stories into soluons. 󷇴󷇵󷇶󷇷󷇸󷇹

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SECTION-C

5. (a) What is a string? Explain any ve string manipulaon funcons.

(b) Write a program to get a string from user and count number of vowels in it.

Ans: (a) Once upon a me in the Kingdom of Data...

In the magical land of Computeria, where data lived in peace, there were many dierent

types of data cizens: numbers, decimals, booleans, and one of the most expressive of them

all — Strings.

Among all data types, String was the most talkave. While numbers could only count, and

booleans could only say "true" or "false", strings could speak, write names, compose

sentences, and even form stories. If you ever typed a name like "Rishabh", a sentence like

"Welcome to Easy2Siksha", or even a message like "Error: Page not found", you were dealing

with strings.

So, what exactly is a string?

󼨻󼨼 Denion of a String:

In programming, a string is a sequence of characters — leers, numbers, symbols, or spaces

— enclosed in quotaon marks (single ' ' or double " ").

Examples:

• "Hello" – A simple string

• "1234" – Even though it looks like a number, it’s a string if in quotes

• "Welcome to Easy2Siksha" – A string with spaces

In simple words, a string is anything you can type on your keyboard and put inside quotes.

That could be a name, address, sentence, code, or even a paragraph!

Now that you’ve met our character “String,” let’s explore ve magical powers or string

manipulaon funcons that help us work with strings in programming.

These funcons are like tools in a wizard’s kit, used to twist, shape, analyze, and transform

strings into whatever form we need!

󺫦󺫤󺫥󺫧 1. length() – The Measuring Tape

Once upon a class in Easy2Siksha Academy, a student asked,

“How long is my string?”

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That’s when the length() funcon came to the rescue.

󹴡󹴵󹴣󹴤 Purpose: It tells us how many characters are in a string (including spaces and symbols).

󹳴󹳵󹳶󹳷 Example:

text = "Hello World"

print(len(text)) # Output: 11

󼨐󼨑󼨒 Even the space between “Hello” and “World” is counted! This funcon is helpful when

you want to check passwords, usernames, or message lengths.

󺫦󺫤󺫥󺫧 2. lower() and upper() – The Voice Changers

Let’s imagine a situaon. You are lling out a form that asks your name in capital leers, but

you typed it in small leers.

These two funcons help:

• upper() makes everything UPPERCASE

• lower() makes everything lowercase

󹳴󹳵󹳶󹳷 Example:

name = "Rishabh"

print(name.upper()) # Output: RISHABH

print(name.lower()) # Output: rishabh

󼨐󼨑󼨒 These are useful for case-insensive comparisons, formang text for display, or even for

shoung in a message (just kidding — but it works!).

󺫦󺫤󺫥󺫧 3. replace() – The Quick Switcher

This funcon is like a magician who can change words instantly.

Let’s say you wrote:

"I love Python"

But you now want it to say:

"I love Java"

Just use the replace() funcon!

󹳴󹳵󹳶󹳷 Example:

sentence = "I love Python"

print(sentence.replace("Python", "Java")) # Output: I love Java

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󼨐󼨑󼨒 It’s useful when correcng text, replacing sensive informaon, or even eding mulple

sentences in a chatbot!

󺫦󺫤󺫥󺫧 4. strip() – The Cleaner

Once in Computeria, a string walked into a database with muddy shoes — that is, extra

spaces before or aer it!

That’s when the strip() funcon politely cleaned it up.

󹳴󹳵󹳶󹳷 Example:

word = " Easy2Siksha "

print(word.strip()) # Output: Easy2Siksha

󼨐󼨑󼨒 strip() removes extra spaces from the beginning and end of a string. There’s also lstrip()

(le strip) and rstrip() (right strip).

This is especially useful in data entry, forms, and when you're taking input from users.

󺫦󺫤󺫥󺫧 5. split() – The String Slicer

Here’s another tale.

A teacher received a string from a student:

"apple,banana,grape"

But the teacher wanted to grade each fruit separately. So, she used split() — the slicer

funcon that turns a string into a list of items.

󹳴󹳵󹳶󹳷 Example:

fruits = "apple,banana,grape"

print(fruits.split(",")) # Output: ['apple', 'banana', 'grape']

󼨐󼨑󼨒 It’s helpful in reading CSV les, breaking sentences into words, or separang data for

processing.

󽄻󽄼󽄽 Why Are These Funcons Important?

Think of a string like a sentence in real life — we oen:

• Count the number of words (like length)

• Change tone (like upper/lower)

• Replace words

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• Clean up spacing

• Break it apart

These are the same things we do with strings in programming. That’s why string

manipulaon funcons are taught early — they are simple but powerful tools that help you

control and format the way data is shown and handled.

󼪀󼪃󼪄󼪁󼪅󼪆󼪂󼪇 Final Wrap-Up (in plain words):

• A string is just text inside quotaon marks.

• It can be manipulated using many built-in funcons in programming.

• These funcons save me, avoid errors, and make your code smart and clean.

󷙎󷙐󷙏 Summary Table:

Funcon

Purpose

Example Output

len()

Count characters

"Hello" → 5

upper()

Convert to uppercase

"rishabh" → "RISHABH"

replace()

Replace a part of the string

"hi" → "hello"

strip()

Remove extra spaces

" Easy2Siksha " → "Easy2Siksha"

split()

Break string into parts

"a,b,c" → ['a', 'b', 'c']

So next me you see a line of text on a screen, remember — it’s a string that might have

been measured, cleaned, capitalized, or split, thanks to these magical funcons.

(b) Write a program to get a string from user and count number of vowels in it.

Ans: Once Upon a Time in the Kingdom of Code...

In a magical land where computers and codes lived like friends, there was a curious young

student named Anya. She had just started learning programming and was fascinated by how

words and leers could talk to a machine. One day, her mentor gave her a challenge:

"Dear Anya, can you write a small program that takes a sentence from the user and counts

how many vowels are hidden inside it?"

Anya smiled, ready for the challenge. But before wring the code, she decided to

understand everything step by step, like solving a fun mystery.

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Step 1: Understanding the Problem Like a Detecve

When Anya looked at the queson, she realized it’s not just about wring code — it’s about

telling the computer how to think. So she broke it down:

• The computer must ask the user to enter a sentence or a string.

• Then, it must look at each leer of that string, one by one.

• Whenever it nds a vowel (like a, e, i, o, u), it should count it.

• At the end, it should display the total number of vowels found.

Step 2: The Vowel Team

Anya remembered a story her teacher once told:

The vowels – A, E, I, O, U – were like superheroes of the English language. They appeared in

almost every word to make it complete. So, in the code, Anya had to look for these leers,

both in lowercase and uppercase (because 'A' and 'a' are both vowels).

So, the superhero team would be:

a, e, i, o, u, A, E, I, O, U

Step 3: The Code

Now that she had the plan, Anya wrote the following code in Python:

# Get input from the user

user_input = input("Enter a string: ")

# Dene vowels

vowels = "aeiouAEIOU"

# Inialize counter

vowel_count = 0

# Loop through each character in the string

for char in user_input:

if char in vowels:

vowel_count += 1

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# Display the result

print("Number of vowels:", vowel_count)

Step 4: Explaining the Code Like a Story

Let’s now walk through what this code is doing, just like Anya would explain it to her lile

brother:

1. input("Enter a string: ")

The computer is asking the user politely: "Please tell me a sentence."

2. vowels = "aeiouAEIOU"

This line tells the computer: "Hey! Here’s the list of heroes we are searching for!"

3. vowel_count = 0

We start with zero because we haven’t found any vowels yet.

4. for char in user_input:

The computer goes on a leer-by-leer adventure inside the sentence.

5. if char in vowels:

At each step, it checks: "Is this leer a vowel?"

6. vowel_count += 1

If yes, it proudly says: "Aha! Found one!" and increases the count.

7. print("Number of vowels:", vowel_count)

Finally, it tells the user how many vowels it found.

Why This Code is Smart and Simple

• It works with any kind of sentence – short, long, uppercase, or lowercase.

• It avoids complicated logic – just a simple loop and a condion.

• The use of vowels = "aeiouAEIOU" makes it clean and readable.

A Second Story: The Classroom Surprise

A few days later, during a coding compeon in her school, Anya’s teacher gave the same

queson to everyone. While others panicked, Anya smiled. She had already cracked this

puzzle once.

She typed her program condently, and guess what? She even helped others understand it

using the same superhero story of vowels. The teacher was so impressed that he said:

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"Anya, you didn’t just solve the problem – you taught it like a true coder."

Moral of the Story

Programming isn’t just about wring code – it’s about understanding the logic, simplifying it,

and explaining it like a story so that even a beginner can enjoy the journey.

So next me you write a program, remember Anya’s steps:

• Understand the problem

• Break it into simple tasks

• Write readable code

• And most importantly, make it fun!

6. What is Recursion? Write a program to nd factorial of a given number using recursive

funcon.

Ans: 󷇴󷇵󷇶󷇷󷇸󷇹 Once Upon a Time in a Village of Mathemagicians...

In a quiet village where numbers came alive, there lived a wise old Mathemagician named

Rishi. He was known for solving the biggest problems with the smallest steps. One day, a

curious lile boy named Arjun came to him and asked:

“Master Rishi, I heard people talking about this magical thing called recursion. What is it?”

The old man chuckled and said,

“Ah, recursion! It’s like asking someone to do a job, and that someone says — ‘Sure! But

rst, let me ask another person to do a smaller part of it for me. When they’re done, I’ll

complete my part too!’”

Arjun was confused. So Rishi explained it with a real-life example.

󷏙󷏚󷏛󷏜 Story of the Magical Mirror

“Imagine you stand in front of two mirrors facing each other,” said Rishi. “You see an image

of yourself, then another image behind that, and then another… and it goes on and on unl

it becomes too ny to see. That’s how recursion works in programming — a funcon keeps

calling itself again and again with smaller inputs, unl it reaches a point where it stops —

known as the base case.”

Now Arjun was geng interested!

Rishi connued,

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“Let me show you a magic trick with numbers — the factorial. You know what 5 factorial

means, right?”

Arjun replied,

“Yes! 5! = 5 × 4 × 3 × 2 × 1 = 120.”

Rishi smiled.

“Exactly! But instead of mulplying all the numbers manually, what if we made a funcon

that solves it step-by-step using recursion? Let me show you how.”

󼨐󼨑󼨒 Understanding Factorial Recursively

Let’s break it down:

• 5! = 5 × 4!

• 4! = 4 × 3!

• 3! = 3 × 2!

• 2! = 2 × 1!

• 1! = 1 (this is the base case — the smallest problem that we can solve directly)

So, to solve 5!, we just need to solve 4!, and to solve 4!, we need 3!, and so on. This chain

connues unl we reach 1, and then everything starts resolving backward, just like climbing

down a ladder and then back up.

This is recursion in acon — solving a big problem by breaking it into smaller copies of the

same problem!

󹲙󹲚󹲛󹲜󹲝󹲞 Now, Let’s Write the Magic (C Program)

#include <stdio.h>

// Recursive funcon to calculate factorial

int factorial(int n) {

if (n == 0 || n == 1) {

// Base case: factorial of 0 or 1 is 1

return 1;

} else {

// Recursive case: n * factorial of (n-1)

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return n * factorial(n - 1);

}

int main() {

int number;

prin("Enter a number to nd its factorial: ");

scanf("%d", &number);

if (number < 0) {

prin("Factorial is not dened for negave numbers.\n");

} else {

prin("Factorial of %d is %d\n", number, factorial(number));

}

return 0;

}

󼨻󼨼 Explanaon of the Code Like a Story

Let’s imagine the funcon factorial(n) as a character named Funky Factorial, who receives a

number n and has a job to nd its factorial.

• If n is 1 or 0, Funky says:

“Easy peasy! The factorial is just 1. I’m done!”

• But if n is more than 1, Funky says:

“Hmm, too big! I’ll ask my younger brother Funky(n - 1) to do it for me, and I’ll mulply the

result by n.”

This connues down unl Funky(1) says,

“I’ve got this! Returning 1!”

Then, like magic, each Funky funcon passes the result back up:

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• Funky(2) returns 2 × 1 = 2

• Funky(3) returns 3 × 2 = 6

• Funky(4) returns 4 × 6 = 24

• Funky(5) returns 5 × 24 = 120

And just like that, the factorial of 5 is found through recursion!

󼨐󼨑󼨒 Why is Recursion Special?

Recursion is like a superpower in programming. It helps us solve complex problems in a neat,

elegant way, especially when the problem can be broken down into similar smaller problems

— like tree structures, puzzles, or mathemacal series.

But just like magic, recursion should be used carefully. Without a base case, it would go on

forever — like falling into an endless mirror loop!

󽄻󽄼󽄽 Final Words

So, whenever you hear the word recursion, think of a team of helpers, each solving a smaller

task and passing the answer back — like a relay race. And when used right, it makes

problems like factorials, Fibonacci numbers, tower of Hanoi, and more look like child’s play!

Next me you see a big problem, don’t panic. Just ask yourself,

“Can I solve a smaller version of this and build up to the full answer?”

That’s the recursive way — small steps, big soluons.

SECTION-D

7. What is structure in C? Which are types of structures ? Explain the uses of structures:

Give an example.

Ans: In that classroom, there’s a teacher named Mr. Sharma, who is known for his unique

way of taking aendance. Instead of calling names and checking roll numbers from a

marks, and grade. Every me he checks aendance, he opens a student’s notebook and sees

all the informaon together.

Now imagine if Mr. Sharma had to keep four dierent registers — one for names, one for roll

numbers, one for marks, and one for grades. That would be confusing, right?

This is exactly what structures in C solve.

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So, What is a Structure in C?

In C programming, a structure (or struct) is a user-dened data type that allows you to

combine dierent types of data items together under one name.

While arrays can hold mulple values of the same type, structures can hold values of

dierent types. That’s the beauty of it.

So, instead of storing a student’s name (string), roll number (int), marks (oat), and grade

(char) in dierent variables, you can put them all together in one unit — a structure.

Think of a structure like a custom data container or a mini database record. It groups related

informaon, just like a folder holds dierent papers about the same student.

󼨻󼨼 Why Do We Need Structures?

Let’s take a very small example:

char name[20];

int rollNo;

oat marks;

char grade;

This is ne if you are dealing with just one student. But what if there are 50 students?

You’ll end up having 4 separate arrays, and you’ll have to remember that name[3], rollNo[3],

marks[3], and grade[3] all belong to the same student. That’s messy.

But using structures, you can dene a student blueprint and then create 50 student records

easily.

󷧺󷧻󷧼󷧽󷨀󷧾󷧿 Dening a Structure

Here’s how we dene a structure in C:

struct Student {

char name[20];

int rollNo;

oat marks;

char grade;

};

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Here, Student is a structure type that holds four dierent pieces of data — each of a

dierent type.

You can now create a variable of type struct Student like this:

struct Student s1;

This s1 can now hold all the data related to one student.

󼨻󼨼 Types of Structures in C

In C, structures can be used in dierent ways, leading to dierent types or usage paerns:

1. Simple Structure

This is the most basic form, like the one shown above. It holds dierent data types together.

2. Array of Structures

You can create an array where each element is a structure.

struct Student students[50];

This is perfect for handling mulple records.

3. Nested Structures

A structure can contain another structure as its member.

struct Date {

int day, month, year;

};

struct Student {

char name[20];

int rollNo;

struct Date dob; // Date of Birth

};

This shows how structures can be nested to represent more complex informaon.

4. Pointer to Structure

You can also create pointers to structures and dynamically allocate memory using malloc.

struct Student *ptr;

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ptr = (struct Student*) malloc(sizeof(struct Student));

Useful for handling data in heap memory or with linked lists.

󷗭󷗨󷗩󷗪󷗫󷗬 Uses of Structures in C

Structures are extremely useful, especially when you are dealing with real-life enes or

complex data. Here are some key uses:

󷃆󼽢 1. Handling Real-World Data

Structures help model real-world enes — like students, employees, books, customers, etc.

󷃆󼽢 2. Creang Complex Data Structures

Structures are the foundaon of more advanced data structures like linked lists, trees,

stacks, queues, etc.

󷃆󼽢 3. Funcon Argument Grouping

Instead of passing mulple variables to a funcon, you can pass one structure that contains

all necessary data.

󷃆󼽢 4. File Handling

When saving data to les (like saving student records), structures help you read and write an

enre record at once.

󷃆󼽢 5. Modular Programming

Structures help organize code beer by grouping related variables, which makes large

programs easier to manage and debug.

󹴡󹴵󹴣󹴤 Example with Explanaon

Let’s write a simple C program using structures.

#include <stdio.h>

struct Student {

char name[20];

int rollNo;

oat marks;

char grade;

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};

int main() {

struct Student s1 = {"Ravi", 101, 89.5, 'A'};

prin("Student Informaon:\n");

prin("Name: %s\n", s1.name);

prin("Roll No: %d\n", s1.rollNo);

prin("Marks: %.2f\n", s1.marks);

prin("Grade: %c\n", s1.grade);

return 0;

}

󹲹󹲺󹲻󹲼󹵉󹵊󹵋󹵌󹵍 Output:

Student Informaon:

Name: Ravi

Roll No: 101

Marks: 89.50

Grade: A

This simple program creates a structure Student, stores the informaon of a student named

"Ravi", and then prints it.

󹴮󹴯󹴰󹴱󹴲󹴳 A Short Story: The Library System

Imagine you are designing a library system. Each book has:

• A tle (string),

• An author (string),

• A book ID (integer),

• A price (oat)

If you try to manage each piece of informaon in dierent arrays, it becomes very hard to

match book IDs with tles and authors.

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But with a structure like this:

struct Book {

char tle[50];

char author[50];

int bookID;

oat price;

};

Now you can easily manage an array of books. You can store, search, and update informaon

easily. Structures make your program look organized, logical, and closer to real life.

󷃆󼽢 Conclusion

A structure in C is a powerful feature that allows you to create your own data types by

combining variables of dierent types under one name. It is like a container or record that

keeps all related informaon together.

From students and employees to books and bank accounts, structures help us model real-

world objects in programming. They are also the foundaon of more complex systems.

In short:

• Structures make code clean, organized, and real-life-oriented.

• They are easy to use, exible, and essenal for data management in C.

So next me you see a messy collecon of related variables, think like Mr. Sharma and put

them all in a neat structure! 󺅕󺅓󺅖󺅗󺅘󺅔

8. What is a pointer ? How are pointers helpful in accessing an array ? Explain

call by reference.

Ans: In a small digital kingdom inside a computer, there lived a smart lile postman named

Pointer. Unlike normal messengers, Pointer didn't carry any leers or packages. Instead, he

carried something even more powerful—addresses.

You see, every house (memory locaon) in the kingdom had a unique number—just like real-

world addresses. All the data (like numbers, characters, arrays, etc.) lived in these houses.

So, whenever someone wanted to nd a piece of data, they would ask Pointer, because he

knew exactly where it was located.

Let’s now break down Pointer’s story and how he helps us in programming.

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󷃆󼽢 What is a Pointer?

In simple terms, a pointer is a variable that stores the memory address of another variable.

Let’s take an example:

int num = 10;

int *ptr = &num;

• Here, num is a normal variable holding the value 10.

• &num means “address of num”.

• ptr is a pointer to an integer, and it's storing the address of num.

So now, ptr doesn't store 10. It stores the locaon where 10 is kept. And using that locaon,

it can indirectly access or modify the value of num.

󷃆󼽢 Why are Pointers Useful?

You might wonder, “Why not just use num directly?” Great queson! The power of pointers

comes when we want to deal with arrays, funcons, memory management, or large data

structures. Let’s look at how Pointer helps with arrays.

󼪟󼪠󼪡 How are Pointers Helpful in Accessing an Array?

Imagine an array is like a row of houses, each with a number (index) and each holding a

value (like books in shelves).

int arr[5] = {10, 20, 30, 40, 50};

In memory, these values are stored side by side. The pointer to the rst element of the array

is:

int *ptr = arr; // or int *ptr = &arr[0];

Now comes the magic! Just by using the pointer ptr, we can move from one house to

another.

*(ptr + 0) = 10

*(ptr + 1) = 20

*(ptr + 2) = 30

So, instead of wring arr[2], we can write *(ptr + 2) to get the same value!

Pointers allow us to navigate through arrays easily without using index notaon. This is

extremely useful in cases like:

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• Passing arrays to funcons

• Dynamic memory allocaon

• Iterang through data eciently

󼨐󼨑󼨒 Call by Reference – The Real Power of Pointers

Let’s now understand call by reference, a concept that makes pointers even more magical.

󹴮󹴯󹴰󹴱󹴲󹴳 Mini Story: The Chef and the Recipe

There was once a famous chef named Maya. She had a student named Rohan who always

wanted to improve her recipes. One day, Rohan asked Maya for her original recipe book.

Maya was smart and didn't give him the whole book. Instead, she gave him a copy. Rohan

made changes in the copy, but Maya’s original recipe remained untouched.

This is like call by value—we pass a copy of the variable to a funcon, so changes inside the

funcon don’t aect the original variable.

But what if Maya gave Rohan the address of her original recipe book? Now, whatever Rohan

changes will directly aect the original! This is call by reference.

󼨽󼨾󼨿󼩁󼩀 Technical Explanaon

In call by reference, we pass the address of a variable to a funcon, and any changes made

inside the funcon are reected in the original variable.

Example:

void update(int *p) {

*p = *p + 10;

}

int main() {

int num = 20;

update(&num);

cout << num; // Output: 30

}

Here’s what happens:

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1. num is 20.

2. update(&num) sends the address of num to the funcon.

3. Inside the funcon, *p means “go to that address and update the value”.

4. So, the original num becomes 30.

This is very helpful when we want a funcon to modify original data, save memory, or deal

with large objects (like arrays, strings, etc.) eciently.

󷃆󼽢 Why Do Examiners Love Answers with Pointers?

Because they show that the student:

• Understands memory concepts.

• Can write ecient programs.

• Knows how data moves inside a computer.

• Can use powerful techniques like dynamic memory, arrays, structures, and recursion.

󹲹󹲺󹲻󹲼󹵉󹵊󹵋󹵌󹵍 Conclusion

To sum up:

• A pointer is a variable that stores the address of another variable.

• Pointers are helpful in accessing arrays by navigang through memory addresses

instead of indices.

• In call by reference, we use pointers to allow funcons to modify the original values,

making code more ecient and powerful.

Whether it's the postman in the digital kingdom or the chef who gave away her recipe’s

address—pointers are like magical keys that unlock the doors of real power in programming!

“This paper has been carefully prepared for educaonal purposes. If you noce any mistakes or

have suggesons, feel free to share your feedback.”