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

我试图删除类对象数组中的特定元素。我用它之后的元素覆盖我要删除的元素。我的算法工作但输出不正确，经过调试并逐步完成代码后，似乎我的对象只是不复制，有没有办法复制类对象，我已经查找了复制构造函数并尝试编写一个但是它似乎对输出没有任何影响。我将不胜感激任何帮助。感谢

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()返回实例的firstname成员变量的副本。为该函数的输出分配另一个值不会更改实例本身中存储的值。请改用player[i-1].setFirstName(player[i].getFirstName())。此外，您可以使用赋值运算符via，而不是复制for循环中的每个成员 player[i-1] = player[i];