chap11 reference

最新推荐文章于 2024-08-13 20:41:11 发布

转载最新推荐文章于 2024-08-13 20:41:11 发布 · 339 阅读

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#reference #pointers #object #null #语言 #c

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本文详细介绍了C++中引用与指针的区别，包括初始化、重新赋值及空值的可能性等方面，并通过示例代码展示了如何操作引用和指针。

There are certain rules when using references:

(1)A reference must be initialized when it is created. (Pointers can be initialized at any
time.)
(2)Once a reference is initialized to an object, it cannot be changed to refer to another
object. (Pointers can be pointed to another object at any time.)
(3)You cannot have NULL references. You must always be able to assume that a reference is
connected to a legitimate piece of storage.

改变指针自身的值
在C语言里，e.g
void f(int** ppi)
{
   (*ppi)++;
}

int main()
{
   int* i = 0;
   cout<<"i = "<<i<<endl;//i = 0
   f(&i);
   cout<<"i = "<<i<<endl;//i = 1
   return 0;
}

why?
需要自增一个指针(int *pi)所指向的内容时，可以(*pi)++
同理，自增指针(int *pi)自身的值时，指针同样有另外的指针(int **ppi)指向它,
可以(*ppi)++。

在C++里，可以使用pointer reference
void f(int* &pi)
{
  pi++;
}

int main()
{
   int* i = 0;
   cout<<"i = "<<i<<endl;//i = 0
   f(i);
   cout<<"i = "<<i<<endl;//i = 1
   return 0;
}