比较两个向量以获得公共元素/定义user1和user2

Question

我有一个User类,私人用户可以个性化用户的个人资料,例如姓名,年龄,收藏夹.我想比较两个给定用户的收藏夹并输出常见的收藏夹.因为我将使用向量,我的问题是如何将用户分组到vector(user1,user2),这样我就可以比较任何给定成员的收藏并输出结果.这就是我到目前为止所拥有的

user.cpp

 using namespace std;

 vector<string> user;


 int  adduser();
 int adduser()
 {

   ofstream thefile;  
   thefile.open("users.txt", ios::app);

   string firstname;
   string lastname;
   int age;
   string favourites;

   cout<<"Enter your  Name: ";
   cin>>name;
   thefile << name << ' ';

   cout<<"Enter your age: ";

   cin>>age;
   thefile << age << ",";

   cout<<"Enter your favourites: ";

   cin>>favourites;
   thefile << favourites<< ",";

   thefile.close();
   cout<<" Completed."<<endl;
   return 0;
 }
 common favourites()
 {

 //how do make it so i have something like user1 and user2 
 //which are both vectors so when i enter the name of 
 //user1 and user2 i can compare thier favourites and output the common ones


 }  

Answer 1

您可以使用<algorithms>库,假设您可以对向量进行排序:

std::sort(user1.begin(), user1.end());
std::sort(user2.begin(), user2.end());
std::vector<string> common;

std::set_intersection(user1.begin(), user1.end(), user2.begin(), user2.end(), std::back_inserter(common));