C ++重载数组运算符 [英] C++ overloading array operator

问题描述

我正在创建一个堆，像这样:

I'm creating a Heap, like this:

struct Heap{
    int H[100];
    int operator [] (int i){return H[i];}
    //...    
};

当我尝试从中打印元素时，我会这样做:

When I try to print elements from it I do like this:

Heap h;
//add some elements...
printf("%d\n", h[3]); //instead of h.H[3]

我的问题是，是否要像这样访问而不是设置它们:

My question is, if instead of accessing I want to set them, like this:

for(int i = 0; i < 10; i++) h[i] = i;

我该怎么办?我不能只是这样做...

How can I do? I can't just do this way i did...

谢谢！

推荐答案

常见的是提供operator[]函数的几个重载-一个重载const对象，另一个重载非const对象. const成员函数的返回类型可以是const&或仅仅是一个值，具体取决于要返回的对象，而非const成员函数的返回类型通常是引用.

It is idiomatic to provide couple of overloads of the operator[] function - one for const objects and one for non-const objects. The return type of the const member function can be a const& or just a value depending on the object being returned while the return type of the non-const member function is usually a reference.

struct Heap{
    int H[100];
    int operator [] (int i) const {return H[i];}
    int& operator [] (int i) {return H[i];}
};

这允许您使用数组运算符修改非const对象.

This allows you to modify a non-const object using the array operator.

Heap h1;
h1[0] = 10;

，同时仍然允许您访问const对象.

while still allowing you to access const objects.

Heap const h2 = h1;
int val = h2[0];

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