Reorder Array acc to given index

#include<iostream> 
  
using namespace std; 
  
// Function to reorder elements of arr[] according 
// to index[] 
void reorder(int arr[], int index[], int n) 
{ 
    int temp[n]; 
  
    // arr[i] should be present at index[i] index 
    for (int i=0; i<n; i++) 
        temp[index[i]] = arr[i]; 
  
    // Copy temp[] to arr[] 
    for (int i=0; i<n; i++) 
    {  
       arr[i]   = temp[i]; 
       index[i] = i; 
    } 
} 
  
// Driver program 
int main() 
{ 
    int arr[] = {50, 40, 70, 60, 90}; 
    int index[] = {3,  0,  4,  1,  2}; 
    int n = sizeof(arr)/sizeof(arr[0]); 
  
    reorder(arr, index, n); 
  
    cout << "Reordered array is: \n"; 
    for (int i=0; i<n; i++) 
        cout << arr[i] << " "; 
  
    cout << "\nModified Index array is: \n"; 
    for (int i=0; i<n; i++) 
        cout << index[i] << " "; 
    return 0; 
}