C++ cout 不是 std 的成员
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cout is not a member of std
提问by Paul Hannon
I'm practicing using mulitple files and header files etc. So I have this project which takes two numbers and then adds them. Pretty simple.
我正在练习使用多个文件和头文件等。所以我有这个项目，它需要两个数字然后将它们相加。很简单。
Here are my files:
这是我的文件：
main.cpp
主程序
#include <iostream>
#include "add.h"
int main()
{
int x = readNumber();
int y = readNumber();
writeAnswer(x + y);
return(0);
}
io.cpp
io.cpp
int readNumber()
{
int x;
std::cout << "Number: ";
std::cin >> x;
return x;
}
void writeAnswer(int x)
{
std::cout << "Answer: ";
std::cout << x;
}
add.h
添加.h
#ifndef ADD_H_INCLUDED
#define ADD_H_INCLUDED
int readNumber();
void writeAnswer(int x);
#endif // #ifndef ADD_H_INCLUDED
The error is showing up in io.cpp. The exact errors are:
错误显示在 io.cpp 中。确切的错误是：
Does anyone have any idea why this may be happening? Thanks.
有谁知道为什么会发生这种情况？谢谢。
EDIT: I made a small project yesterday with the same amount of files (2 .cpp and 1.h) and I didn't include the iostream header in the other .cpp and it still compiled and ran fine.
编辑：我昨天用相同数量的文件（2 .cpp 和 1.h）做了一个小项目，我没有在另一个 .cpp 中包含 iostream 头文件，它仍然编译并运行良好。
回答by unkulunkulu
add #include <iostream>to the start of io.cpptoo.
添加#include <iostream>到io.cpp太开始。
回答by Jukes
Also remember that it must be:
还要记住，它必须是：
#include "stdafx.h"
#include <iostream>
and not the other way around
而不是相反
#include <iostream>
#include "stdafx.h"
回答by Marco Rubio
I had a similar issue and it turned out that i had to add an extra entry in cmaketo include the files.
我有一个类似的问题，结果我不得不添加一个额外的条目cmake来包含这些文件。
Since i was also using the zmq library I had to add this to the included libraries as well.
由于我也在使用 zmq 库，因此我也必须将其添加到包含的库中。
