HW6_PI

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
// x^2 + y^2 = 1
double y(double x)
{
    return  sqrt(1 - pow(x,2)) ;
}

int main(int argc, char *argv[])
{
    double i,A=0 ;

    for(i=-1;i<0 ; i = i+0.1)
    {
        A += (y(i+0.1)-y(i)) * 0.1 ;
    }
    A = A * 4 ;
    printf("%.5f\n",A);
    return 0;
}