#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);
}