在VC ++类中使用指针

问题描述

大家好

我必须通过使用指针函数来面对类中的问题.
例如

头文件

testPtr.h

Hi All

I have to face problem in classes by using pointers function.
for example

header file

testPtr.h

class testPtr
{
    float *add(float *a,int n)
};

主要是该类的使用

in main the use of this class

   //testing.cpp 

// object of class
testPtr testPtrObject();

void main
{

testPtrObject.add(a,n);

}


float testPtr::*add(float a int n)

{

----------
-------
}

我只在有指针的情况下才可以面对问题
否则，如果我在头文件中使用简单的函数，然后通过在主类中创建该类的对象来调用这些函数，那么我可以轻松地访问该函数，并通过创建该类的对象来使用它们，只要我需要它

请指导我在使用指针函数

i ve to face the problem only in case of pointer
other wise if i use simple functions in header file and then call these function by creating the objects of that class in main class i can easily access that functions and use them any whaere i neede by creating the object of that class

kindly guide me what to do in case of pointer function

推荐答案

typedef float* (testPtr::*MemFuncPtr) (float *a, int n);
MemFuncPtr p = &testPtr::add;

// calling sequence:
(testPtrObject.*p) (&a, n);

如您所见，语法很尴尬，是C ++的弱点之一.

与其将函数的指针和对象的指针分开处理，不如将它们捆绑在一起成为一个对象.这就是通常所说的委托.

您可以在CodeProject上找到很多有关委托的好文章，例如:

成员函数指针和最快的C ++代理

希望您能走上正轨.

As you see, the syntax is awkward and one of the weaker points of C++.

Instead of handling the pointer to function and the object pointer separately, why not bundle them together into a single object. That''s what is generally called a delegate.

You find a lot of good articles here on CodeProject about delegates, for example this one:

Member Function Pointers and the Fastest Possible C++ Delegates

Hope that gets you on track.

class testPtr
{
public:
    float *add(float *a,int n);
};

实现应如下所示:

The implementation should look like this:

float* testPtr::add(float* a int n)
{
//----------
//-------
}

然后可以这样使用:

It can then be used like this:

int main()
{
  testPtr testPtrObject;
  float b = 1.0;
  float* a =&b;
  int n = 2;
  float* c = testPtrObject.add(a,n);

  testPtr* testPtrObjectPtr = new testPtr();
  float* c = testPtrObjectPtr->add(a,n);
  delete testPtrObjectPtr;


  }

这篇关于在VC ++类中使用指针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！