int-int-int.c

int a[] = { 1,2,3,4,5,6,7,8,9 };
int b[] = { 2,4,8,12,16,18 };
int *c;

int main() {
  int i, j, k;

  c = malloc(sizeof(a) + sizeof(b));

  for (i = 0, j = 0, k = 0; i < sizeof(a)/sizeof(int) && j < sizeof(b)/sizeof(int); ) {
    if (a[i] == b[j]) {
      c[k] = a[i];
      i++, j++, k++;
    } else if (a[i] < b[j]) {
      i++;
    } else if (a[i] > b[j]) {
      j++;
    }
  }

  for (int l = 0; l < k; l++) {
    printf("%d\n", c[l]);
  }

  return 0;
}