Area of Circle Program in C

In this blog post, we will checkout the area of circle program in C programming. The area of a circle is given by the formula ( πr^2 ), where ( r ) is the radius of the circle and (π) (Pi) is a constant approximately equal to 3.14159. This formula is a cornerstone in geometry and is pivotal in various applications across science and engineering fields. Our focus will be on implementing this formula in a C program to efficiently compute the area, providing a practical approach to understanding mathematical concepts through programming.

Area of Circle Formula

Area =  π * Radius * Radius

Where value of pie = 3.14159 and radius will be given by the user.

How to Write Area of Circle Program in C?

To create a C program for finding the area of a circle, you can follow this algorithm and corresponding pseudo code.

Algorithm:

1. Start: Begin the process.
2. Input Radius: Prompt the user to input the radius of the circle.
3. Calculate Area: Use the formula Area = π * Radius * Radius to calculate the area of the circle.
4. Display Area: Show the calculated area to the user.
5. End: Conclude the process.

Pseudo Code:

BEGIN
    DECLARE radius, area AS FLOAT
    PRINT "Enter the radius of the circle: "
    READ radius
    area = π * radius * radius
    PRINT "The area of the circle with radius ", radius, " is: ", area
END

C Program to Find Area of Circle

#include <stdio.h>

int main() {
    double radius, area;
    // initializing the value of pi
    double pi = 22.0 / 7.0;

    // Prompt user and get radius
    printf("Enter the radius of the circle: ");
    scanf("%lf", &radius);  // %lf for reading double

    // Calculate area
    area = pi * radius * radius;  // M_PI is from math.h

    // Display the area
    printf("The area of the circle with radius %.2lf is: %.2lf\n", radius, area);

    return 0;  // End of program
}

Output

In the above program, first, we initialise the variable pi with the value of π and take input for radius then using the area of circle formula calculated the area of the circle.

Time Complexity: The time complexity of this program is O(1). This is because the calculation of the area of a circle is achieved through a straightforward arithmetic expression that does not depend on iterative or recursive processes.

Space Complexity: The space complexity is also O(1). This is because program uses few variables which doesn’t not grow with the input size.

Conclusion

• On a plane, a shape’s area is the amount of space it covers.
• When the radius is given, the area of a circle is Area=π∗(radius)2Area=π∗(radius)2
• Using the above we have discussed area of circle program in C.

If you liked this post you can checkout other C Programs.

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