Answer:
#include <iostream>
using namespace std;
void findDuplicate(int arr[], int size) {
for(int i = 0; i < size; ++i) {
for(int j = i+1; j < size; ++j) {
if(arr[j] == arr[i]) {
cout << arr[j] << endl;
return;
}
}
}
cout << -1 << endl;
}
int main() {
int arr[] = {2, 3, 5, 6, 11, 20, 4, 8, 4, 9};
findDuplicate(arr, 20);
return 0;
}
Step-by-step explanation: