C++用random_shuffle打乱字符串数组顺序

有一点不好的是，randNum的取值会影响随机次序，如果randNum定了的话，无论程序运行多少遍，次序都不会变。

#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

int main()
{
    
  vector<string> vs;
  string name[] = {"徐晓寒", "韩青", "杨惠", "王忠超", 
                    "申子欣", "张茵", "叶白璐", "王斌", "章莹婷"};
  int nameSize = sizeof(name) / sizeof(string);
  for(int i = 0; i < nameSize; i++)
  {
      vs.push_back(name[i]);
  }
  
  int vsSize = vs.size();
  int randNum = 200;
  for(int i = 0; i < randNum; i++)
  {
      random_shuffle(vs.begin(), vs.end());
  }

  for (int i = 0; i < vsSize; i++)
  {
      cout << "第 " << i + 1 << " 位   " << vs[i] << endl;
  }
  
  return 0;
}

因为以上代码固定randNum的取值，每次运行，打乱的次序不变，不过添加一行srand(unsigned(time(NULL)));
就能使得打乱次序改变了。

#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;

int main()
{
  srand(unsigned(time(NULL)));
  vector<string> vs;
  string name[] = {"徐晓寒", "韩青", "杨惠", "王忠超", 
                    "申子欣", "张茵", "叶白璐", "王斌", "章莹婷"};
  int nameSize = sizeof(name) / sizeof(string);
  for(int i = 0; i < nameSize; i++)
  {
      vs.push_back(name[i]);
  }
  
  int vsSize = vs.size();
  int randNum = 200;
  for(int i = 0; i < randNum; i++)
  {
      random_shuffle(vs.begin(), vs.end());
  }

  for (int i = 0; i < vsSize; i++)
  {
      cout << "第 " << i + 1 << " 位   " << vs[i] << endl;
  }
  
  return 0;
}