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，如下所示:

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，我喜欢这样:

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，如果不是访问我想设置它们，像这样:

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?我不能就那样做...

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

谢谢！

推荐答案

提供 operator[] 函数的几个重载是惯用的 - 一个用于 const 对象一个用于非const 对象.const 成员函数的返回类型可以是 const& 或只是一个值，这取决于返回的对象，而非const 成员函数通常是一个引用.

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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