当我使用我的输入时，我的 C++ 程序没有打印任何输出

Question

我正在开发一个 C++ 程序。在

main()

功能中，它会要求用户输入他们朋友的名字和姓氏，以及他们的爱好。例如，用户输入将是这样的：

Erik,French,soccer,END
Jenna,Obrien,soccer,games,END
Ricardo,Waters,games,baseball,END

然后将输出用户列表和按拥有这些兴趣的用户数量排名的前 5 位兴趣。

当我运行我的程序并输入时，程序没有输出任何输出。

而不是这个输出：

我尝试使用

if

语句

break

，但它仍然显示相同的结果。

if (hobby != "done"){
    users.push_back(user);
}else break;

有什么办法可以解决这个问题吗？

主要

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include "User.h"

using namespace std;

int main()
{
    vector<User> users;
    vector<string> allHobbies;
    string firstname, lastname, hobby, done;
    
    while (cin >> firstname >> lastname) {
        string friendsname = firstname + " " + lastname;
        User user(friendsname);
        
        while (cin >> hobby && hobby != "END") {
            user.AddHobby(hobby);
            allHobbies.push_back(hobby);
        }
        if (hobby != "done"){
            users.push_back(user);
        }else break;
    }
    
    // Print users
    cout << "The Users" << endl;
    cout << "=========================" << endl;
    for (const auto& user : users) {
        cout << user.GetName() << endl;
    }
    
    // Count hobby occurrences
    sort(allHobbies.begin(), allHobbies.end());
    auto last = unique(allHobbies.begin(), allHobbies.end());
    vector<pair<string, int>> hobbyCounts;
    for (auto it = allHobbies.begin(); it != last; ++it) {
        hobbyCounts.push_back(make_pair(*it, count(allHobbies.begin(), allHobbies.end(), *it)));
    }
    
    // Sort by count and print top 5
    sort(hobbyCounts.begin(), hobbyCounts.end(), [](const auto& p1, const auto& p2) {
        return p1.second > p2.second;
    });
    
    cout << "The Top 5 Hobby Metrics" << endl;
    cout << "=========================" << endl;
    cout << "Rank\tHobby\tCount" << endl;
    cout << "=========================" << endl;
    int i = 1;
    for (const auto& p : hobbyCounts) {
        if (i > 5) break;
        cout << i++ << "\t" << p.first << "\t" << p.second << endl;
    }
    
    return 0;
}

用户.h

#ifndef USER_H
#define USER_H

#include <string>
#include <vector>

class User {
public:
    User(const std::string& name);
    void AddHobby(const std::string& hobby);
    const std::vector<std::string>& GetHobbies() const;
    std::string GetName() const;
    
private:
    std::string friendsname;
    std::vector<std::string> hobbies_;
};

#endif

用户.cpp

#include "User.h"

User::User(const std::string& name) {
    this->friendsname = name;
}

void User::AddHobby(const std::string& hobby) {
    this->hobbies_.push_back(hobby);
}

const std::vector<std::string>& User::GetHobbies() const {
    return hobbies_;
}

std::string User::GetName() const {
    return friendsname;
}

Answer 1

输入最后一个用户后按 CTRL-D。

这会关闭 cin 并退出循环。你然后得到你的输出

pal moo
a b END
p d
d f END  
>>>>>>>>> ==== CTRL-D here
The Users
=========================
pal moo
p d
The Top 5 Hobby Metrics
=========================
Rank    Hobby   Count
=========================
1       a       1
2       b       1
3       d       1
4       f       1

Answer 2

查看代码后，发现代码中有错误导致程序过早退出。具体来说，代码行

if (hobby != "done")

应该是

if (firstname != "done")

，因为 firstname 是从 cin 中读取的变量，以获取朋友的名字。

这里是代码的更正版本：

int main()
{
    vector<User> users;
    vector<string> allHobbies;
    string firstname, lastname, hobby, done;

    while (cin >> firstname >> lastname) {
        string friendsname = firstname + " " + lastname;
        User user(friendsname);

        while (cin >> hobby && hobby != "END") {
            user.AddHobby(hobby);
            allHobbies.push_back(hobby);
        }

        if (firstname != "done") {
            users.push_back(user);
        } else {
            break;
        }
    }

    // Print users
    cout << "The Users" << endl;
    cout << "=========================" << endl;
    for (const auto& user : users) {
        cout << user.GetName() << endl;
    }

    // Count hobby occurrences
    sort(allHobbies.begin(), allHobbies.end());
    auto last = unique(allHobbies.begin(), allHobbies.end());
    vector<pair<string, int>> hobbyCounts;
    for (auto it = allHobbies.begin(); it != last; ++it) {
        hobbyCounts.push_back(make_pair(*it, count(allHobbies.begin(), allHobbies.end(), *it)));
    }

    // Sort by count and print top 5
    sort(hobbyCounts.begin(), hobbyCounts.end(), [](const auto& p1, const auto& p2) {
        return p1.second > p2.second;
    });

    cout << "The Top 5 Hobby Metrics" << endl;
    cout << "=========================" << endl;
    cout << "Rank\tHobby\tCount" << endl;
    cout << "=========================" << endl;
    int i = 1;
    for (const auto& p : hobbyCounts) {
        if (i > 5) break;
        cout << i++ << "\t" << p.first << "\t" << p.second << endl;
    }

    return 0;
}