c++ - 左移位运算符重载

Question

大家好，

我正在尝试重载左移位运算符<<，以执行以下操作：

char value[] = "Hello";
value << 2;

这样做时，我希望将其打印为：“val”，因此要删除最后两个字符；我的问题是我无法正确声明我的重载函数。

我的代码是：

//the .h file    
#pragma once
#include <iostream>

class Operators
{
public:
    char *word;
    int number;

    Operators(void);
    Operators(char str[], int num);
    ~Operators(void);
    void Print(void);
    friend char & operator<<(char &stream, int &nr);     
};

#include "StdAfx.h"
#include "Operators.h"
#include <iostream>

Operators::Operators(void)
{
    word = "";
    number = 0;
}

Operators::Operators(char *str, int num)
{
    word = str;
    number = num;
}

Operators::~Operators(void)
{
}

void Operators::Print(void)
{
    printf("\nThe String: %s", word);
}

friend char & operator<<(char &stream, int &nr)
{

    return stream;
}

// Operator_Overloading.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "Operators.h"
#include <conio.h>
#include <iostream>

using namespace std;


int _tmain(int argc, _TCHAR* argv[])
{
    char value[] = "Hello";
    Operators op(value, 2);


    op.Print();

    _getch();
    return 0;
}

Answer 1

You cannot overload any of the operators if they don't involve, at least, one user defined type. Your use case involves a char[N] and an int, i.e., you can't overload any operators for these arguments.