我需要帮助，试图找出删除数组中元素的逻辑

Question

我有一个使用这段代码的作业，但我需要它才能开始工作。除了removeFollowers函数之外，一切都按预期工作。它最终会删除正确的跟随器，但是当再次打印数组时，它会造成混乱并重复现有的追随者。我知道问题在于removeFollowers函数的逻辑，但我似乎无法让它正常工作。

以下是头文件、主文件、当前输出和预期输出：

#ifndef TWITTERPROJECT_H_INCLUDED
#define TWITTERPROJECT_H_INCLUDED
#include<iostream>
using namespace std;


template <class T>
class Twitter {

    private:
        string name;
        T followers[5];
        int numFollowers;

    public:
        Twitter(string x);
        void addFollower(T follower); //takes in follower to add
        bool removeFollower(T follower); //takes follower to remove
        void printFollowers(); //doesn't take any parameters
};

template <class T>
Twitter<T>::Twitter(string x) { //constructor
    name = x;
    numFollowers = 0; //starts out with zero followers
}

template <class T>
void Twitter<T>::addFollower(T follower) {

    if (numFollowers < 5) {

        followers[numFollowers] = follower;
        numFollowers++;

    }
    else{
        cout<<"Error, this user already has maximum followers" << endl; }
}

template <class T>
bool Twitter<T>::removeFollower(T follower) {

    for(int i=0;i<numFollowers;i++){

            if(followers[i] == follower){

                for(int j = i + 1; j < numFollowers; j++){

                        followers[j - 1] = followers[j];
                        numFollowers--;
                        return true;
                }
            return false;
            }

    }
    cout << endl;
}

template <class T>
void Twitter<T>::printFollowers() {

    cout << "Followers for " << name << ": " << endl;

    for(int i = 0; i < numFollowers; i++)

    cout << followers[i] << endl;}

#endif // TWITTERPROJECT_H_INCLUDED

#include <iostream>
#include "TwitterProject.h"

using namespace std;

struct Profile {
    string userName;
    int age;
    string state;
};

ostream& operator << (ostream & output, const Profile & p) {
    output << p.userName;
    return output;
} //overloading the insertion operator <<


bool operator == (const Profile &p1, const Profile &p2)
{
    return p1.userName == p2.userName;
} //overloading the == operator for the removeFollower method



int main()
{

    Twitter<string> e1("Sara");
    Twitter<Profile> e2("Ty");

//adding followers of type string to user Sara (also string)
    cout << "Adding followers to Sara" << endl;
    e1.addFollower("Rapunzel");
    e1.addFollower("Flynn");
    e1.addFollower("Cinderella");
    e1.addFollower("Prince Charming");

//printing Sara's followers
    e1.printFollowers();
    cout << endl;


//creating profiles of type username
    Profile p1 = {"Rue", 18, "Michigan"};
    Profile p2 = {"Jules", 22, "California"};
    Profile p3 = {"Fez", 30, "Alaska"};
    Profile p4 = {"Maddie", 21, "Colorado"};
    Profile p5 = {"Cassie", 24, "Maine"};


//adding profile followers to Ty user (profile)
    cout << "Adding follower profiles to Sara" << endl;
    e2.addFollower(p1);
    e2.addFollower(p2);
    e2.addFollower(p3);
    e2.addFollower(p4);
    e2.addFollower(p5);

//printing Ty's followers
    e2.printFollowers();
    cout << endl;

//demonstrating removing followers from both users
    cout << "Removing follower Flynn from Sara" << endl;
    e1.removeFollower("Flynn");
    cout << "Removing follower Prince Charming from Sara" << endl;
    e1.removeFollower("Prince Charming");
    e1.printFollowers();
    cout << endl;

    cout << "Removing Jule's profile from Ty" << endl;
    e2.removeFollower(p2);
    e2.printFollowers();
    cout << endl;


    return 0;
}

Adding followers to Sara
Followers for Sara:
Rapunzel
Flynn
Cinderella
Prince Charming

Adding follower profiles to Sara
Followers for Ty:
Rue
Jules
Fez
Maddie
Cassie

Removing follower Flynn from Sara
Removing follower Prince Charming from Sara

Followers for Sara:
Rapunzel
Cinderella
Cinderella

Removing Jule's profile from Ty
Followers for Ty:
Rue
Fez
Fez
Maddie

--预期产出-预期产出

Adding followers to Sara
Followers for Sara:
Rapunzel
Flynn
Cinderella
Prince Charming

Adding follower profiles to Sara
Followers for Ty:
Rue
Jules
Fez
Maddie
Cassie

Removing follower Flynn from Sara
Removing follower Prince Charming from Sara

Followers for Sara:
Rapunzel
Cinderella

Removing Jule's profile from Ty
Followers for Ty:
Rue
Fez
Maddie
Cassie

任何帮助、暗示或线索都是非常感谢的。(非常感谢:)

Answer 1

我不太理解你在移除器函数中的逻辑，但我认为你在尝试做什么，或者沿着这些思路做些什么:找到跟随者去删除，将数组从索引后移到一个空格，减少追随者的数量？

我认为您可能会采取一种更简单的方法，只需用数组的最后一个元素交换找到的元素，并减少关注者的数量。

所以你的功能应该是这样的？

template <class T>
bool Twitter<T>::removeFollower(T follower) {

    
    for(int i=0;i<numFollowers;i++){
        if(followers[i] == follower){       
            T tmp = followers[i];
            followers[i] = followers[numFollowers-1];
            followers[numFollowers-1] = tmp;

            --numFollowers;
            return true;
        }
    }
    return false;
}

就个人而言，我不建议在这种类型的事情上使用数组。向量是删除和添加元素的一个更好的选择。

邮递员还没对这个做过测试，如果有打字的话.

Answer 2

在函数removeFollower的内循环中

for(int j = i + 1; j < numFollowers; j++){

        followers[j - 1] = followers[j];
        numFollowers--;
        return true;
}

一旦一个元素被复制到数组的前一个元素中，函数就会退出。因此，如果不是数组的最后一个元素，相同的元素实际上是重复的。

可以声明该函数(我更改了函数参数的类型)并定义了以下方式

template <class T>
bool Twitter<T>::removeFollower( const T &follower ) 
{
    int i = 0;

    while ( not ( i == numFollowers ) && not ( followers[i] == follower ) ) i++;

    bool success = i != numFollowers;

    if ( success )
    {
        while ( ++i != numFollowers )
        {
            followers[i - 1] = followers[i];
        }
        --numFollowers;
    }
 
    return success;
}

该功能保证在其执行后，追随者的顺序不会改变，这看起来很自然。