Find Duplicate in Range 0 and n-1

Code

#include <stdio.h>

int find_duplicate(int arr[], int n) {
    // Your logic here
   int i;
    for( i=0;i<n-1;i++)
    {
        while(i>n-1){
        if(arr[i]==arr[i+1])
        {
            break;
        }
        }
    }
    return arr[i];
    
}

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;
}

Solving Approach