#include <stdio.h>
#include <math.h>
#define PI 3.14159265
int main () {
double x, y, ret, val;
x = -7.0;
y = 7.0;
val = 180.0 / PI;
ret = atan2 (y,x) * val;
printf("The arc tangent of x = %lf, y = %lf ", x, y);
printf("is %lf degrees\n", ret);
return(0);
}
