C Basics, Variables & Data Types Practice Questions with Solutions

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C is one of the most popular programming languages and is often called the foundation of modern programming. Developed by Dennis Ritchie in 1972, C is widely used for building operating systems, embedded systems, databases, compilers, and high-performance applications.

Learning C helps you understand programming fundamentals such as variables, data types, operators, memory management, and functions. Mastering these concepts makes it easier to learn advanced programming languages like C++, Java, Python, and C#. C Basics, Variables & Data Types practice questions with solutions help to understand the concepts.

In this chapter, you’ll practice beginner-friendly C programming questions focused on variables and data types. Every question includes a complete C solution, sample output, explanation, and key concepts, making it ideal for beginners, students, coding interviews, and programming practice.

1. C Program to Print “Hello, World!”

Problem Statement

Write a C program to print “Hello, World!” on the screen.

C Solution

#include <stdio.h>

int main()
{
    printf("Hello, World!");

    return 0;
}

Sample Output

Hello, World!

Explanation

  • #include <stdio.h> includes the Standard Input Output library.
  • main() is the starting point of every C program.
  • printf() displays text on the screen.
  • return 0; indicates that the program executed successfully.

Concepts Covered

  • First C Program
  • Header Files
  • printf()
  • main() Function

2. C Program to Print Your Name

Problem Statement

Write a C program to print your name.

C Solution

#include <stdio.h>

int main()
{
    printf("My name is Rahul.");

    return 0;
}

Sample Output

My name is Rahul.

Explanation

The printf() function prints the text exactly as written inside double quotation marks.

Concepts Covered

  • Output Statements
  • printf()
  • Basic Program Structure

3. C Program to Declare and Print an Integer Variable

Problem Statement

Write a C program to declare an integer variable and display its value.

C Solution

#include <stdio.h>

int main()
{
    int age = 21;

    printf("Age = %d", age);

    return 0;
}

Sample Output

Age = 21

Explanation

  • int declares an integer variable.
  • %d is the format specifier used to print integer values.
  • The variable age stores the value 21.

Concepts Covered

  • Variables
  • Integer Data Type
  • Format Specifier %d

4. C Program to Declare and Print a Float Variable

Problem Statement

Write a C program to declare a floating-point variable and display its value.

C Solution

#include <stdio.h>

int main()
{
    float percentage = 87.5;

    printf("Percentage = %.1f", percentage);

    return 0;
}

Sample Output

Percentage = 87.5

Explanation

  • float is used to store decimal numbers.
  • percentage is a floating-point variable.
  • %.1f displays the value with one digit after the decimal point.

Concepts Covered

  • Float Data Type
  • Floating-Point Variables
  • Format Specifier %f

5. C Program to Declare and Print a Character Variable

Problem Statement

Write a C program to declare a character variable and display its value.

C Solution

#include <stdio.h>

int main()
{
    char grade = 'A';

    printf("Grade = %c", grade);

    return 0;
}

Sample Output

Grade = A

Explanation

  • char is used to store a single character.
  • Character values are enclosed in single quotation marks (' ').
  • %c is the format specifier used to print character values.

Concepts Covered

  • Character Data Type
  • Character Variables
  • Format Specifier %c

6. C Program to Declare and Print Multiple Variables

Problem Statement

Write a C program to declare multiple variables of different data types and display their values.

C Solution

#include <stdio.h>

int main()
{
    int age = 21;
    float height = 5.9;
    char grade = 'A';

    printf("Age = %d\n", age);
    printf("Height = %.1f\n", height);
    printf("Grade = %c", grade);

    return 0;
}

Sample Output

Age = 21
Height = 5.9
Grade = A

Explanation

The program demonstrates how different data types can be declared and printed in the same program using appropriate format specifiers.

Concepts Covered

  • Multiple Variables
  • Integer
  • Float
  • Character
  • printf()

7. C Program to Find the Size of Basic Data Types Using sizeof()

Problem Statement

Write a C program to display the size of basic data types using the sizeof() operator.

C Solution

#include <stdio.h>

int main()
{
    printf("Size of int = %lu bytes\n", sizeof(int));
    printf("Size of float = %lu bytes\n", sizeof(float));
    printf("Size of char = %lu bytes\n", sizeof(char));
    printf("Size of double = %lu bytes", sizeof(double));

    return 0;
}

Sample Output

Size of int = 4 bytes
Size of float = 4 bytes
Size of char = 1 bytes
Size of double = 8 bytes

Note: Output may vary depending on your compiler and operating system.

Explanation

The sizeof() operator returns the amount of memory (in bytes) occupied by a data type or variable.

Concepts Covered

  • sizeof()
  • Memory Allocation
  • Data Types

8. C Program to Swap Two Numbers Using a Third Variable

Problem Statement

Write a C program to swap two numbers using a temporary variable.

C Solution

#include <stdio.h>

int main()
{
    int first = 10;
    int second = 20;
    int temp;

    temp = first;
    first = second;
    second = temp;

    printf("First Number = %d\n", first);
    printf("Second Number = %d", second);

    return 0;
}

Sample Output

First Number = 20
Second Number = 10

Explanation

A temporary variable stores the value of the first variable before the values are exchanged.

Concepts Covered

  • Variables
  • Swapping
  • Temporary Variable

9. C Program to Swap Two Numbers Without Using a Third Variable

Problem Statement

Write a C program to swap two numbers without using a temporary variable.

C Solution

#include <stdio.h>

int main()
{
    int first = 10;
    int second = 20;

    first = first + second;
    second = first - second;
    first = first - second;

    printf("First Number = %d\n", first);
    printf("Second Number = %d", second);

    return 0;
}

Sample Output

First Number = 20
Second Number = 10

Explanation

The program swaps values using arithmetic operations instead of a temporary variable.

Concepts Covered

  • Swapping
  • Arithmetic Operations
  • Variables

10. C Program to Display the ASCII Value of a Character

Problem Statement

Write a C program to display the ASCII value of a character.

C Solution

#include <stdio.h>

int main()
{
    char character = 'A';

    printf("ASCII Value = %d", character);

    return 0;
}

Sample Output

ASCII Value = 65

Explanation

Every character has a unique ASCII value. When a character is printed using the %d format specifier, C automatically displays its corresponding ASCII code.

Concepts Covered

  • ASCII Values
  • Character Data Type
  • Type Conversion

11. C Program to Read and Display an Integer Value

Problem Statement

Write a C program to accept an integer from the user and display it.

C Solution

#include <stdio.h>

int main()
{
    int number;

    printf("Enter an integer: ");
    scanf("%d", &number);

    printf("You entered: %d", number);

    return 0;
}

Sample Output

Enter an integer: 25
You entered: 25

Explanation

The scanf() function reads input from the keyboard, while printf() displays the entered value.

Concepts Covered

  • scanf()
  • User Input
  • Integer Variables

12. C Program to Read and Display a Float Value

Problem Statement

Write a C program to accept a floating-point number from the user and display it.

C Solution

#include <stdio.h>

int main()
{
    float salary;

    printf("Enter your salary: ");
    scanf("%f", &salary);

    printf("Salary = %.2f", salary);

    return 0;
}

Sample Output

Enter your salary: 35000.50
Salary = 35000.50

Explanation

The %f format specifier is used with both scanf() and printf() to work with floating-point values.

Concepts Covered

  • Float Variables
  • scanf()
  • User Input

13. C Program to Read and Display a Character

Problem Statement

Write a C program to accept a character from the user and display it.

C Solution

#include <stdio.h>

int main()
{
    char grade;

    printf("Enter a grade: ");
    scanf(" %c", &grade);

    printf("Grade = %c", grade);

    return 0;
}

Sample Output

Enter a grade: A
Grade = A

Explanation

A space before %c in scanf() ignores any leftover newline characters from previous input.

Concepts Covered

  • Character Input
  • scanf()
  • Character Variables

14. C Program to Display Values of Different Data Types

Problem Statement

Write a C program to declare variables of different data types and display them together.

C Solution

#include <stdio.h>

int main()
{
    int age = 22;
    float percentage = 91.4;
    char grade = 'A';

    printf("Age = %d\n", age);
    printf("Percentage = %.1f\n", percentage);
    printf("Grade = %c", grade);

    return 0;
}

Sample Output

Age = 22
Percentage = 91.4
Grade = A

Explanation

This program demonstrates how different data types can be used together in a single program.

Concepts Covered

  • Integer
  • Float
  • Character
  • Multiple Variables

15. C Program to Display Default Format Specifiers

Problem Statement

Write a C program to print different data types using their correct format specifiers.

C Solution

#include <stdio.h>

int main()
{
    int number = 100;
    float price = 49.99;
    char letter = 'C';

    printf("Integer : %d\n", number);
    printf("Float   : %.2f\n", price);
    printf("Character : %c\n", letter);

    return 0;
}

Sample Output

Integer : 100
Float   : 49.99
Character : C

Explanation

Different data types require different format specifiers while displaying output.

Concepts Covered

  • Format Specifiers
  • printf()
  • Data Types

Chapter Summary

In this chapter, you learned the fundamentals of C programming, including variables, data types, format specifiers, user input, and basic input/output functions. You practiced creating variables, printing values, accepting user input using scanf(), displaying ASCII values, swapping variables, and understanding how memory is allocated using sizeof(). These concepts form the foundation for writing efficient C programs and are essential before learning operators, conditional statements, loops, and functions.

Key Takeaways

  • C is a procedural programming language widely used for system and application development.
  • Variables are used to store data in memory.
  • Common data types include int, float, char, and double.
  • printf() displays output, while scanf() accepts user input.
  • Every data type has its own format specifier.
  • sizeof() helps determine the memory occupied by a data type.
  • Characters are internally stored as ASCII values.
  • Swapping variables is a common programming exercise.
  • Understanding variables and data types is essential before learning advanced C concepts.
  • Strong fundamentals make learning C++, Java, and Python much easier.

Frequently Asked Questions (FAQs)

1. What is the C programming language?

C is a general-purpose, procedural programming language developed by Dennis Ritchie. It is widely used for system programming, embedded systems, and application development.

2. What is a variable in C?

A variable is a named memory location used to store data that can change during program execution.

3. What are the basic data types in C?

The most commonly used data types are:

  • int
  • float
  • char
  • double

4. What is the difference between printf() and scanf()?

  • printf() is used to display output.
  • scanf() is used to accept input from the user.

5. What is a format specifier?

A format specifier tells printf() and scanf() what type of data is being printed or read, such as %d, %f, and %c.

6. What does the sizeof() operator do?

The sizeof() operator returns the amount of memory (in bytes) occupied by a data type or variable.

7. What is an ASCII value?

An ASCII value is the numeric representation of a character used internally by computers.

8. Why should beginners learn C before other programming languages?

Learning C builds a strong understanding of programming fundamentals, memory management, variables, data types, and problem-solving skills, making it easier to learn advanced programming languages later.

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

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