Random

#include <stdio.h>
#include <stdlib.h>
int main(void) {
  int i,num = 500;
  double x[num];
  double y[num];
  srand(149);
  for (i = 0; i < num; i++) {
    x[i] = -5.0 + ((double) rand()) / RAND_MAX * 10.0;
    y[i] = -5.0 + ((double) rand()) / RAND_MAX * 10.0;
    if (x[i] * x[i] + y[i] * y[i] > 25.0) i--;
  }
  for (i = 0; i < num; i++)
    printf("% g % g % g\n", x[i], y[i], x[i] * x[i] + y[i] * y[i]);
  return 0;
}