prefix sum array

#include <bits/stdc++.h> 
using namespace std; 

void fillPrefixSum(int arr[], int n, int prefixSum[]) 
{ 
    prefixSum[0] = arr[0]; 
    for (int i = 1; i < n; i++) 
        prefixSum[i] = prefixSum[i-1] + arr[i]; 
} 
 
int main() 
{ 
    int arr[] = { 10, 4, 16, 20 }; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    int prefixSum[n]; 
  
    fillPrefixSum(arr, n, prefixSum); 
    for (int i = 0; i < n; i++) 
        cout << prefixSum[i] << " "; 
}