#include <stdio.h>
int main() {
// arr must not contain any element more than twice
// if that may be the case, choose the alternative approach
int arr[] = { 2, 4, 5, 6, 4, 8, 9, 2 };
int count = 0;
for (int i = 0, size = sizeof(arr) / sizeof(int); i < size; i++) {
int it = arr[i];
for (int i2 = i + 1; i2 < size; i2++) {
int it2 = arr[i2];
if (it != it2) continue;
count++;
break;
}
}
printf("%d duplicates found.", count);
}