構造体，並べ替え

struct person {
  char name[64];
  double height, weight;
};

void swap(double *a, double *b)
{
  double  tmp;
  tmp = *a; *a = *b; *b = tmp;
}

void sort_by_height(struct person data[], int size)
{
  int minpos, i, j;
  
  for (i = 0; i < size-1; i++) {
    minpos = i;
    for (j = i+1; j < size-1; j++) {
      if (data[j]  < data[minpos] ) {
	minpos = j;
      }
    }
    swap( data[j] ,  data[minpos] );
  }
}