SD and Min

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define N 10
static double *input(void){
  char buf[BUFSIZ];
  double *dat = (double *) malloc(N * sizeof(double));
  int i = 0;
  double d;
  while (i < N) {
    printf("Input %d: ", i + 1);
    fgets(buf, BUFSIZ, stdin);
    d = atof(buf);
    if (d <= 0) continue;
    dat[i++] = d;
  }
  return dat;
}
static double com1(double *dat) {
  double sum = 0., average, diff = 0.;
  int i;
  for (i = 0; i < N; i++) sum += dat[i];
  average = sum / N;
  for (i = 0; i < N; i++) diff += (dat[i] - average) * (dat[i] - average);
  return sqrt(diff / N);
}
static double com2(double *dat) {
  double min = dat[0];
  int i;
  for (i = 1; i < N; i++) if (min > dat[i]) min = dat[i];
  return min;
}
int main(void) {
  double *dat = input();
  printf("Standard Diviation: %lf\n", com1(dat));
  printf("Minimum: %lf\n", com2(dat));
  return 0;
}