c++ - 如何将对象数组中的内容复制到 C++ 中的另一个数组中？

Question

#include "stdafx.h"
#include<iostream>
using namespace std;
class bank
{
public: char name[20];
public: float balance;
public: void get()
{
    cout << "\nEnter name and balance in Account respectively\n";
    cin >> name >> balance;
}
public: void display()
{
    cout << "Name: " << name << "    Balance: " << balance;
}
};
void main()
{
    int i = 0;
    bank b[10];
    bank max;
    bank temp;
    for (i = 0; i < 10; i++)
    {
        b[i].get();
    }
    for (i = 0; i < 10; i++)
    {
        if (b[i + 1].balance > b[i].balance)
        {
            max.balance = b[i + 1].balance;
            max.name = b[i + 1].name;//Error 1 error C2106: '=' : left operand must be l-value
        }
        else
        {
            temp.balance = b[i + 1].balance;
            temp.name = b[i + 1].name;//Error 2 error C2106: '=' : left operand must be l-value
            b[i + 1].balance = b[i].balance;
            b[i + 1].name = b[i].name;//Error 3 error C2106: '=' : left operand must be l-value
            b[i].balance = temp.balance;
            b[i].name = temp.name;//Error 4 error C2106: '=' : left operand must be l-value
            max.balance = b[i + 1].balance;
            max.name = b[i + 1].name;//Error 5  error C2106: '=' : left operand must be l-value
        }

    }
    max.display();
}

在这个程序中，我必须将输入作为 10 个人的姓名和余额，并将输出显示为对应于最高余额的姓名和余额。除了代码本身作为注释显示的错误之外，我还在相同的那些行中获得了另一个代码，仅在我对错误进行注释的地方。另一个错误是:

IntelliSense: expression must be a modifiable lvalue

我使用的是 Visual Studio Professional 2013，代码是 Visual C++

Answer 1

您不能分配 char[]变量到另一个char[]多变的。你应该使用 strcpy功能来做到这一点(并且不要忘记先include<cstring>)。看到这个 how to copy char array to another char array in C?进一步解释。

如果这样改，应该没问题:

#include<iostream>
#include<cstring>
using namespace std;
class bank
{
    public: char name[20];
    public: float balance;
    public: void get()
    {
        cout << "\nEnter name and balance in Account respectively\n";
        cin >> name >> balance;
    }
    public: void display()
    {
        cout << "Name: " << name << "    Balance: " << balance;
    }
};
void main()
{
    int i = 0;
    bank b[10];
    bank max;
    bank temp;
    char tempstr[20]; // use this for temporary string
    for (i = 0; i < 3; i++)
    {
        b[i].get();
    }
    for (i = 0; i < 2; i++) // you should change the upper bound to 9
                            // so it not crash when i = 9
    {
        if (b[i + 1].balance > b[i].balance)
        {
            max.balance = b[i + 1].balance;
            strcpy(max.name, b[i+1].name); // use strcpy
        }
        else
        {
            temp.balance = b[i + 1].balance;
            strcpy(temp.name, b[i+1].name); // use strcpy
            b[i + 1].balance = b[i].balance;
            strcpy(b[i+1].name, b[i].name); // use strcpy
            b[i].balance = temp.balance;
            strcpy(b[i].name, temp.name); // use strcpy
            max.balance = b[i + 1].balance;
            strcpy(max.name, b[i+1].name); // use strcpy
        }

    }
    max.display();
}