的char * p =＆QUOT; orkut的＆QUOT; VS为const char * p =＆QUOT; orkut的＆QUOT; [英] char *p="orkut" vs const char *p="orkut"

问题描述

 char *p="orkut" vs const char *p="orkut"

什么btwn这两个的区别...

whats the difference btwn these two...

修改

从Bjarne的Stroustrup的，第3版第90页

from bjarne stroustrup,3rd edition page 90

void f()
{

char* p="plato";
p[4]='e' // error: assign to const;result is undefined

}

的这种错误cannont是一般的b抓住，直到运行时间和实现他们的这一规则的实施有所不同的

与为const char * p =同柏拉图

Same with const char *p="plato"

这就是为什么IAM要求探源......请告诉我的常量的意义在这里..

Thats why iam asking the diffrence... Whats the significance of const here..

推荐答案

的为const char * 变种是正确的。

您不应该改变来自一个字符串字面量的内存（称为静态存储通常情况下）。它是只读存储器。

You should not change memory that comes from a string literal (referred to as static storage usually). It is read only memory.

不同的是，在的char * 变种将让你写的语法来更改它通过取消引用它指向的数据。但什么它实际上是不确定的。

The difference is that the char* variant will allow you to write the syntax to change the data that it points to by dereferencing it. What it actually does though is undefined.

//Option 1:
char *p = "orkut";
*p = 'x';//undefined behavior


//Option 2:
const char *q = "orkut";
*q = 'x';//compiling error

我宁愿有选择2发生在我身上。

I would rather have option 2 happen to me.

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