调用成员函数 [英] Call member function

问题描述

我不知道如何从main调用类成员函数。

这里是类的定义：

  class poly 
 {
 private：
 Node * start; 
 public：
 poly（Node * head）/ *构造函数* / 
 {
 start = head; 
} 
 
 void printPoly（）; //  - > Poly * polyObj将是隐式参数?? 
}; 
 
 void poly :: printPoly（）
 {
 // ... 
} 
  

这里是调用代码：

  poly * polyObj; 
 polyObj = processPoly（polyomial）; // processPoly是返回poly * 
的函数polyObj.printPoly（）; //这是问题在哪里是
  

现在我想使用polyObj调用printPoly

解决方案

您必须取消引用指针才能调用该函数。指针包含对象的地址，取消引用返回对象。因此：

 （* polyObj）.printPoly（）; 
  

但是，这通常缩写为：

  polyObj-> printPoly（）; 
  

I don't know how to call a class member function from main. I want to call "printPoly" with a poly object as its implicit parameter.

Here is the class definition:

class poly
{
private:
    Node *start;    
public:
    poly(Node *head)  /*constructor function*/
    {
        start = head;
    }

    void printPoly(); //->Poly *polyObj would be the implicit parameter??
};

void poly :: printPoly()
{
    //....
}

Here is the calling code:

poly *polyObj;
polyObj = processPoly(polynomial); // processPoly is a function that returns a poly *
polyObj.printPoly(); // THIS IS WHERE THE PROBLEM IS

Now I want to call "printPoly" with the polyObj I just created.

解决方案

You must dereference the pointer before you can call the function. The pointer contains the address of the object, dereferencing returns the object. So:

(*polyObj).printPoly();

However, this is usually shortened to:

polyObj->printPoly();

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