编译错误：左边模糊不清，右边模糊

Question

我收到编译错误，说'左'和'右'不明确。

我是否宣布左，右对错？

• 内主声明并没有帮助
• 移动上述主要功能的定义并不能帮助

如何我会解决这个问题？

最少测试用例：

#include <iostream> 
using namespace std; 
int left = 0, right = 0; 
int main() 
{ 
    cout << left; 
    cout << right; 
} 

所赐：

prog.cpp: In function ‘int main()’: 
prog.cpp:6:13: error: reference to ‘left’ is ambiguous 
prog.cpp:3:5: error: candidates are: int left 
In file included from /usr/include/c++/4.7/ios:43:0, 
       from /usr/include/c++/4.7/ostream:40, 
       from /usr/include/c++/4.7/iostream:40, 
       from prog.cpp:1: 
/usr/include/c++/4.7/bits/ios_base.h:918:3: error: 
      std::ios_base& std::left(std::ios_base&) 
prog.cpp:7:13: error: reference to ‘right’ is ambiguous 
prog.cpp:3:15: error: candidates are: int right 
In file included from /usr/include/c++/4.7/ios:43:0, 
       from /usr/include/c++/4.7/ostream:40, 
       from /usr/include/c++/4.7/iostream:40, 
       from prog.cpp:1: 
/usr/include/c++/4.7/bits/ios_base.h:926:3: error: 
      std::ios_base& std::right(std::ios_base&) 

Answer 1

观察错误消息：

raw.cpp:105: error: reference to ‘right’ is ambiguous 
raw.cpp:5: error: candidates are: int right 
/usr/include/c++/4.2.1/bits/ios_base.h:917: error: 
    std::ios_base& std::right(std::ios_base&) 

它恐吓阅读，但基本上这是它说：

raw.cpp:105: error: There's more than one ‘right’ here 
One of them is yours: raw.cpp:5 int right 
Another one isn't: <bits/ios_base.h:917>: some crap in namespace ‘std’ 

因此left和right已在namespace std中定义，您正在导入所有using namespace std。这就是你含糊不清的原因。解决这个问题的最简单的方法是删除using namespace std;并添加using std::cin; using std::cout;，但这看起来像是我的口味中的太多全局变量。

顺便说一句，你应该把你的代码并入你的问题。这个问题在这里可能会比粘贴时间更长，如果没有人能看到整个问题，我的回答就没有意义了。