Find Duplicate in Range 0 and n-1

#include <stdio.h>

int find_duplicate(int arr[], int n) {
    // Your logic here
    int cout , temp = 0;

    for(int i = 0 ; i < n ; i++)
    {
        
        for(int j = i+1 ; j < n ; j++)
        {
            if((arr[i] == arr[j]) && (i != j))
            cout = arr[i] ;
        }
    }
    return cout;
}

int main() {
    int n;
    scanf("%d", &n);

    int arr[100];
    for (int i = 0; i < n; i++) scanf("%d", &arr[i]);

    int result = find_duplicate(arr, n);
    printf("%d", result);
    return 0;
}