Inner Product

#include <stdio.h>
#include <stdlib.h>
int main(void) {
  int x[] = { 1, 2, 3, 4 };
  int y[] = { 4, 3, 2, 1 };
  int e = sizeof(x) / sizeof(int);
  int z[e];
  int i;
  for (i = 0; i < e; i++) {
    z[i] = x[i] * y[i];
  }
  printf("[");
  for (i = 0; i < e; i++) {
    printf("%d", z[i]);
    if (i < e - 1) printf(", ");
  }
  printf("]\n");
  return 0;
}