C ++使用带方括号的指针指向实例 [英] C++ using square brackets with pointer to instance

问题描述

我创建了一个单例类，它使用 GetInstance（）方法来获取实例地址（指针）。
在类中我有一个unsigned long int数组，我创建了 operator [] （直接访问数组）。
我如何使用从 GetInstance 获得的指针以使用 []运算符？
我尝试过：

  class risc {// singleton 
 protected：
 unsigned长寄存器[8]; 
 static risc * _instance; 
 risc（）{
 for（int i = 0; i <8; i ++）{
 registers [i] = 0;}; 
} 
 public：
 unsigned long operator []（int i）const {return registers [i];}; // get [] 
 unsigned long& operator []（int i）{return registers [i];}; // set [] 
 static risc * getInstance（）{// constructor 
 if（_instance == NULL）{
 _instance = new risc（）; 
} 
 return _instance; 
} 
}; 
 
 risc * Risc = getInstance（）; 
 * Risc [X] = ... 
  

。

h2_lin>解决方案

试试这个：

方括号运算符优先于指针解引用运算符。也可以通过名称调用操作符，虽然这会导致一个相当拙劣的语法：

  Risc-> ]（x）= ... 
  

I've created a singleton class which uses GetInstance() method to get the instance address (pointer). Inside the class i have an array of unsigned long int which i've created the operator [] for it (direct access to the array). How can i use the pointer i got from GetInstance in order to use the [] operator ? I've tried :

class risc { // singleton
protected:
unsigned long registers[8];
static risc* _instance;
risc() {
    for (int i=0;i<8;i++) {
        registers[i]=0;};
    }
public:
unsigned long   operator   [](int i) const  {return registers[i];}; // get []
unsigned long & operator   [](int i)        {return registers[i];}; // set []
static risc* getInstance() { // constructor
        if (_instance==NULL) {
            _instance=new risc();
        }
        return _instance;
    }
};

risc* Risc=getInstance();
*Risc[X]=...

But it doesn't work ... is there a way i can use the brackets to access the array directly using the class pointer ?

Thanks !

解决方案

Try this:

(*Risc)[X]=...

The square brackets operator takes precedence over the pointer dereference operator. It is also possible to call the operator by name, although this results in a rather clunky syntax:

Risc->operator[](x) = ...

这篇关于C ++使用带方括号的指针指向实例的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！