C Program to Calculate Area and Perimeter of Square

In this article, you will learn and get code about the program given below:

• Find Area of Square
• Find Area of Square using Function
• Find Perimeter of Square
• Find Perimeter of Square using Function

How to Find Area of Square ?

To find area of square, use the simple formula, area = len*len or area = len². Here len indicates side length of square. As we all knows that all the four side of square is of equal length. Now let's go through the program given below.

Area of Square Program in C

To calculate area of square in C programming, you have to ask from user to enter the side length of square and then perform the simple operation of multiplication of given number with itself (length of square) as shown here in the following program:

#include<stdio.h>
#include<conio.h>
int main()
{
    float len, area;
    printf("Enter length of Square: ");
    scanf("%f", &len);
    area = len*len;
    printf("\nArea = %0.2f", area);
    getch();
    return 0;
}

Here is the sample run of above program. This is the snapshot of initial output:

Enter the length of square say 2.5 and press ENTER key to see the area as shown in the snapshot of final output given below:

Steps used in above Program

Here are the list of some main steps used in above program:

• Declare any two variables of floating-point type. Because side length of square may contain decimal value
• Receive length of square in len variable
• Perform multiplication operation of given value to len variable with itself and initialize it to area variable
• Now just print the value of area as output
• The variable area indicates area of square on output screen
• Here %0.2f is used to print value of area upto 2 decimal places only

Area of Square in C using Function

Now let's create another program that does the same job as of previous program. Except this program is created using function. Let's take a look at it:

#include<stdio.h>
#include<conio.h>
float findAreaSquare(float);
int main()
{
    float len, area;
    printf("Enter length of Square: ");
    scanf("%f", &len);
    area = findAreaSquare(len);
    printf("\nArea = %0.2f", area);
    getch();
    return 0;
}
float findAreaSquare(float leng)
{
    return leng*leng;
}

This program produces same output as of previous program.

How to Find Perimeter of Square ?

To find perimeter of square, use the formula perimeter = 4*side. Here side indicates side length of square. To calculate perimeter, we have to find the boundary length of square. As square has 4 side of equal length, so here we only have to ask for side length, and then just multiply it with 4. That will be perimeter.

Perimeter of Square Program in C

Here is the program in C that calculates perimeter of square of given length (by user at run-time).

#include<stdio.h>
#include<conio.h>
int main()
{
    float len, perimeter;
    printf("Enter length of Square: ");
    scanf("%f", &len);
    perimeter = 4*len;
    printf("\nPerimeter = %0.2f", perimeter);
    getch();
    return 0;
}

When the above c program is compile and executed, it will produce the following result:

You can clearly understand this program with yourself, nothing extra is included here. So I'm going to next program, that is to calculate perimeter of square using function.

Perimeter of Square in C using Function

This is the final program of this article, that does the same job as of previous program, that is, will ask from user to enter side length of square and will calculate perimeter of square but this time using function. Let's have a look at it:

#include<stdio.h>
#include<conio.h>
float findPeriSquare(float);
int main()
{
    float len, perimeter;
    printf("Enter length of Square: ");
    scanf("%f", &len);
    perimeter = findPeriSquare(len);
    printf("\nPerimeter = %0.2f", perimeter);
    getch();
    return 0;
}
float findPeriSquare(float len)
{
    return 4*len;
}

This program produces the same output as of previous program produced. To learn more about function, refer to Function in C tutorial.

C Online Test