c++ implements a sample of recommendation for quicksort input arrays

Without further ado, go straight to the code

#include "stdafx.h"
#include <iostream>
#include <string>
#include <vector>
using namespace std;
void quickSort(vector<int> &a, int, int);
void swap(int &a, int&b);
vector<string> split(string s, string seperator);

int main() {
  string str;
  cout << "please input your array: " << endl;
  getline(cin, str);
  vector<string> strs = split(str, " ");
  cout << "The original array is " << endl;
  for (unsigned int i = 0; i < strs.size(); i++) {
    cout << strs[i] << " ";
  }
  cout << endl;
  vector<int> array(strs.size());
  for (unsigned int i = 0; i < strs.size(); i++) {
    array[i] = atoi(strs[i].c_str());
  }
  int len = array.size();
  cout << "The ordered array is " << endl;
  quickSort(array, 0, len-1);
  for (int i = 0; i < len; i++) {
    cout << array[i] << " ";
  }
  cout << endl;
  system("pause");
  return 0;
}
void quickSort(vector<int> &a, int start, int base) {
  if (start >= base) {
    return;
  }
  int i = start, j = start;
  int temp = a[base];
  for (;j<base;j++) {
    if (a[j]<=temp) {
      swap(a[i], a[j]);
      i++;
    }
  }
  if (a[i] > a[base]) {
    swap(a[i], a[base]);
  }
  quickSort(a, start, i - 1);
  quickSort(a, i + 1, base);
}
void swap(int &a, int&b) {
  if (a == b) {
  }
  else {
    a = a + b;
    b = a - b;
    a = a - b;
  }
  
}
vector<string> split(string s, const string pattern) {
  string::size_type pos;
  vector<string> result;
  s += pattern;
  unsigned int size = s.size();
  for (unsigned int i = 0; i < size; i++) {
    pos = s.find(pattern, i);
    if (pos < size) {
      string str = s.substr(i, pos - i);
      if (!str.empty()){
        result.push_back(str);
      }
      i = pos + pattern.size() - 1;

    }
  }
  return result;
}