问使用动态数组C++11的直方图函数

EN

#include <iostream>
#include <vector>
#include <algorithm>
#include <iomanip>

using namespace std;

void hist(int arr[], int n);

void swap(int &a, int &b);

int main(){
  int* arr = NULL;
  int number;
  cout << "Enter number of grades:" << endl;
  cin >> number;

  cout << "Enter grades (each on a new line):" << endl;
  arr = new int[number];
  for(int i = 0; i < number; i++){
    cin >> arr[i];
  }
  hist(arr, number);
  return 0;
  delete [] arr;
}

void hist(int arr[], int n){
  cout << "Histogram:" << endl;
  for (int i = 0; i < n; i++){
    int j;
    for (j = 0; j < i; j++)
      if(arr[i] == arr[j])
        break;
    if (i == j){
      int xx = count(arr, arr+n, arr[i]);
      cout << setw(3) << arr[i] << " ";
      for (int j = 0; j < xx; ++j){
        cout << "*";
      }
      cout << endl;
    }
  }
}

void swap(int &a, int &b){
  int temp;
  temp = a;
  a = b;
  b = temp;
}