删除存储在数组中的特定类对象

Question

可能重复： Deleting specific class objects stored in an array

我正在尝试删除类对象数组中的特定元素。我正在用后面的元素覆盖我想要删除的元素。我的算法有效，但是输出不正确，经过一步一步的调试，我的对象似乎没有复制，有没有方法复制类对象，我已经查找过复制构造函数并试图编写一个，但它似乎对输出没有任何影响。我很感谢你的帮助。谢谢

下面是我的代码

#include <iostream>
#include <string>
#include <math.h>

using namespace std;

void storeinfo() ;
void showinfo() ;
void menu() ;
void deleteinfo() ;
void displayallinfo() ;
int linsearch(string val) ;


class user 
{
    string firstname, lastname, currentteam, position, status ;
    int age ;
public:
    user() {};
    user(string fname, string lname, string cteam, string pos, string stat, int age) 
    {
        setFirstName(fname);
        setLastName(lname);
        setCurrentTeam(cteam);
        setPosition(pos);
        setStatus(stat);
        setAge(age);
    } ;
    void setFirstName(string fname)
        {firstname = fname;}
    void setLastName(string lname)
        {lastname = lname;}
    void setCurrentTeam(string cteam)
        {currentteam = cteam;}
    void setPosition(string pos)
        {position = pos;}
    void setStatus(string stat)
        {status = stat;}
    void setAge(int _age)
        {age = _age;}

    string getFirstName()
        {return firstname ;}
    string getLastName()
        {return lastname ;}
    string getCurrentTeam()
        {return currentteam ;}
    string getPosition()
        {return position ;}
    string getStatus()
        {return status ;}
    int getAge()
        {return age ;}
};

user player[20] ;
int arrlength = 3 ;

int main()
{
    menu() ;

    cin.get() ;
    return 0 ;
}

void storeinfo()
{
    string firstname ;
    string lastname ;
    string currentteam ;
    string position;
    string status ;
    int age ;

    for (int i=0; i < 3; i++)
    {
        cout << "\n\n Enter First Name : " ; 
        cin >> firstname ;
        player[i].setFirstName(firstname) ;
        cout << "Enter Last Name : " ; 
        cin >> lastname ;
        player[i].setLastName(lastname) ;
        cout << "Enter Player's Age : " ; 
        cin >> age;
        player[i].setAge(age) ;
        cout << "Enter Current Team : " ; 
        cin >> currentteam ;
        player[i].setCurrentTeam(currentteam) ;
        cout << "Enter Position : " ; 
        cin >> position ;
        player[i].setPosition(position) ;
        cout << "Enter Status : " ; 
        cin >> status ;
        player[i].setStatus(status) ;

        cout << "\n\n\n" ;
    }

    /*cout << string(50, '\n');*/

    menu() ;

}

void showinfo()
{
    string search;
    int found ;


    cout << "Please Enter The Player's Last Name : " ;
    cin >> search ;

    found=linsearch(search);

    if (found==-1)
    {
        cout << "\n There is no player called " << search ;
    }
    else
    {
        cout << "\n First Name : " << player[found].getFirstName() << "\n" << "Last Name : " << player[found].getLastName() <<
            "\n" << "Age : " << player[found].getAge() << "\n" << "Current Team : " << player[found].getCurrentTeam() << 
            "\n" << "Position : " << player[found].getPosition() << "\n" << "Status :  " << player[found].getStatus()  << "\n\n";
    }

    cin.get() ;

    menu() ;

}

void deleteinfo()
{
    int arrlength = 3 ;
    string search ;
    int found ;

    cout << "\n Delete A Player's Information \n\n" ;
    cout << "Please Enter The Player's Last Name : " ;
    cin >> search ;

        found=linsearch(search);

    if (found==-1)
    {
        cout << "\n There is no player called " << search ;
    }
    else
    {
        for (int i=found + 1; i < arrlength; ++i)
        {
            player[i-1].setFirstName(player[i].getFirstName()) ;
            player[i-1].setLastName(player[i].getLastName()) ;
            player[i-1].setAge(player[i].getAge()) ;
            player[i-1].setCurrentTeam(player[i].getCurrentTeam()) ;
            player[i-1].setPosition(player[i].getPosition()) ;
            player[i-1].setStatus(player[i].getStatus()) ;
        }

        --arrlength ;


        cout << "\n Player has been deleted." ;
    }

    cin.get() ;

    menu() ;
}

void displayallinfo()
{
    for (int i=0; i < 3; i++)
    {
        cout << "\n First Name : " << player[i].getFirstName() << "\n" << "Last Name : " << player[i].getLastName() <<
            "\n" << "Age : " << player[i].getAge() << "\n" << "Current Team : " << player[i].getCurrentTeam() << 
            "\n" << "Position : " << player[i].getPosition() << "\n" << "Status :  " << player[i].getStatus()  << "\n\n";
    }

    cin.get() ;

    menu() ;
}

void menu()
{
    cout << "\n\n MENU" << "\n" ;
    cout << "\n A. Store Player Information" ;
    cout << "\n B. Show Player Informaton" ;
    cout << "\n C. Delete Player Information" ;
    cout << "\n D. Display All Players";
    cout << "\n Z. Exit \n\n" ;

    string x =  "";
    cin >> x ;

    if (x=="a" | x=="A")
    { 
        storeinfo() ;
    }
    else if (x=="b" | x=="B")
    {
        showinfo() ;
    }
    else if (x=="c" | x=="C")
    {
        deleteinfo() ;
    }
    else if (x=="d" | x=="D")
    {
        displayallinfo() ;
    }
    else if (x=="z" | x=="Z")
    {
        exit(0) ;
    }
    else
    {
        cout << "Invalid Choice" ;
        menu() ;
    }
}

int linsearch(string val)
{
    for (int j=0; j <= 3; j++)
    {
        if  (player[j].getLastName()==val)
         return j ;         
    }
        return -1 ;
}

Answer 1

player[i-1].getFirstName()返回实例名成员变量的副本。将另一个值分配给此函数的输出不会改变存储在实例本身中的值。使用player[i-1].setFirstName(player[i].getFirstName())代替。此外，与其复制for循环中的每个成员，还可以通过player[i-1] = player[i];利用赋值操作程序。

Answer 2

数组确实不适合这类事情。考虑使用std::list。这也意味着你可以摆脱所有笨拙的大小硬编码。