based on a few assumptions, not sure what exactly sc,s1 are supposed do do, but I think I figured what you want.. if this helps
#include <stdio.h>
#include <math.h>
#define PI 3.14159265
#define num_sec 4
int main (){
double x, y, angle, radius;
x = 19.0; //x_coordinate of a point
y = -30.1; //y_coordinate of a point
angle = atan2 (y,x) * 180 / PI; // converting Cartesian plan to polar and radians to degrees also the arc angle are negative so to convert them into positive we add 360 in it.
if (angle < 0) angle += 360;
radius = hypot (x, y); // calculating radius
printf ("For x_cordinate=%f and y_cordinate=%f the Angle=%f and the Radius=%f \n\n",x,y,angle,radius);
int sector[num_sec]={0};
if (radius <= 157.5){
sector[0]++;
}
else if (radius > 157.5 && (angle > 0 && angle <= 120)) {
sector[2]++;
}
else if (radius > 157.5 && (angle > 120 && angle <= 240)) {
sector[1]++;
}
else if (radius > 157.5 && (angle > 240 && angle <= 360)){
sector[3]++;
}
printf ("%d %d %d %d",sector[0],sector[1],sector[2],sector[3]);
return 0;
}