Drawing a cirlce in C without using graphics library

This program utilizes the equation of circle to draw a circle instead of using a graphics library. It makes use of the coordinates of x and y and graphs the circle according to that information. Let us assume that the circle has a center at (0,0). Think in term of limits of the for loops, i.e., where are the corner coordinates of the circle; and then applying an if condition to achieve our required goal.

#include <stdio.h>

int main()
{   //Author : Faizan

    int adia,arow,acol,aradius;
    printf("\t\t * * * * * \n\t PROGRAM TO PRINT A CIRCLE \n\t\t * * * * * \n");
    printf("\n Please Enter Diameter : ");
    scanf_s("%d",&adia);
    aradius=adia/2; // radius determination

    for (arow=aradius; arow>=-arradis; arow--) // y-coordinate
    {   printf("\n\n");
        for (acol=-aradius; acol<=aradius; acol++){ // x-coordinate
                if (acol*acol + arow*arow < aradius*aradius) //equation of the circle
                    printf("# ");
                else
                    printf("  ");
        }
    }
printf("\n");
system("pause");
}

Running the above code yields a diameter x diameter grid and then restricts the printing of building character (here '#') to a circular form as shown in the screenshot at the top of this page.