const char*, char const* and char *const 的区别

关键词: const    char                                          

const char*, char const*, char*const的区别问题几乎是C++面试中每次都会有的题目。

事实上这个概念谁都有只是三种声明方式非常相似很容易记混。
Bjarne在他的The C++ Programming Language里面给出过一个助记的方法:
把一个声明从右向左读。

char * const cp; ( * 读成 pointer to )
cp is a const pointer to char

const char * p;
p is a pointer to const char;

char const * p;
同上因为C++里面没有const*的运算符,所以const只能属于前面的类型。


C++标准规定,const关键字放在类型或变量名之前等价的。

const int n=5;    //same as below
int const m=10;

const int *p;    //same as below  const (int) * p
int const *q; // (int) const *p

char ** p1; 
// pointer to pointer to char
const char **p2;
// pointer to pointer to const char
char * const * p3;
// pointer to const pointer to char
const char * const * p4;
// pointer to const pointer to const char
char ** const p5;
// const pointer to pointer to char
const char ** const p6;
// const pointer to pointer to const char
char * const * const p7;
// const pointer to const pointer to char
const char * const * const p8;
// const pointer to const pointer to const char
 

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