Sorting coordinates

[whitedragon]

My algorithm is unable to successfully sort input in ascending order of the magnitude of hypotenuse from the origin. Please advice on my code written below, thanks.

void sort(point_t arr[], int size) {
int i, j, m, hypo, alt_hypo;
point_t temp;

for(i=0;i<size;i++) {
hypo = (arr[i].x * arr[i].x) + (arr[i].y * arr[i].y);
for(j=i+1,m=i;j<size;j++) {
alt_hypo = (arr[j].x * arr[j].x) + (arr[j].y + arr[j].y);
if(alt_hypo < hypo)
m = j;
}
temp = arr[i];
arr[i] = arr[m];
arr[m] = temp;
}
}

[Stewbond]

Just add an operator< function to your point structure and compare the sum of squares:

struct point_t
{
  double x;
  double y;

  bool operator<(point_t& rhs) { return (x*x+y*y) < (rhs.x*rhs.x + rhs.y*rhs.y); }
} *arr;

std::sort(arr, arr+size);