FYBCom(CA) C practical Slip 1 Q 1. B

Write a C Program to Calculate Area and Circumference Using Function

1. Introduction

In this tutorial, we will learn how to write a simple C program to calculate the area and circumference of a circle using functions. This is a common beginner-level programming question asked in exams and viva.

2. Problem Statement

Question: b) Write a C program to calculate area and circumference using function.
The program should:

• Take the radius of the circle as input from the user
• Use separate functions to calculate area and circumference
• Display the results clearly

3. Logic

We use the formulas:
Area of Circle = π × r × r
Circumference of Circle = 2 × π × r
Steps:

1. Declare function prototypes.
2. Take radius as input.
3. Call functions by passing radius.
4. Print returned values.

4. Source Code (Beginner Friendly)

#include <stdio.h>
float calculateArea(float radius)
{
    float area;
    area = 3.14 * radius * radius;
    return area;
}
float calculateCircumference(float radius)
{
    float circumference;
    circumference = 2 * 3.14 * radius;
    return circumference;
}
int main()
{
    float radius, area, circumference;
    printf("Enter the radius of the circle: ");
    scanf("%f", &radius);
    area = calculateArea(radius);
    circumference = calculateCircumference(radius);
    printf("Area of the circle = %.2f\n", area);
    printf("Circumference of the circle = %.2f\n", circumference);
    return 0;
}

5. Sample Output

Enter the radius of the circle: 5
Area of the circle = 78.50
Circumference of the circle = 31.40

6. Viva Questions (With Answers)

• Q1. What is a function in C?
• Answer: A function in C is a block of code that performs a specific task and can be called whenever required.
• Q2. Why do we use functions in programs?
• Answer: Functions help in code reusability and make programs easier to understand.
• Q3. What is the formula for the area of a circle?
• Answer: Area = π × r × r.
• Q4. What is the return type of a function?
• Answer: It specifies the type of value returned by the function such as int or float.
• Q5. What is the difference between actual and formal parameters?
• Answer: Actual parameters are passed during function call, while formal parameters receive them in the function definition.

Conclusion

This program demonstrates the use of functions in C and is commonly asked in practical exams and viva.