当字符串超出范围时，将string :: c_str（）分配给const char * [英] assigning string::c_str() to a const char* when the string goes out of scope

问题描述

我对基本的C ++用法有疑问。下面的代码使用gcc / LInux编译，可以正确打印。

I have a doubt on basic C++ usage. The code below, compiled with gcc/LInux, prints out correctly.

字符串 test 超出范围，因此也是它的 c_str（）值应该不是吗？我是错还是误解了 const char * 的含义？

The string test goes out of scope so also its c_str() value should be invalid isn't it? Am I wrong or do I have misunderstood the const char*meaning?

   #include <iostream>
   int main(){
     const char* a = "aaaa";
       std::cout << a;
       { std::string test("bbbb");a=test.c_str();}
       std::cout << a;
       a = "cccc";
       std::cout << a;
   }


   aaaabbbbcccc
   // print out without any problem

推荐答案

您是正确的，您的代码无效，因为它使用的对象的生命周期已经结束。它偶然起作用，您不能依靠它。

You're right, your code is not valid since it uses an object whose lifetime has already ended. It works "by accident", you cannot rely on that.

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