\"cout\": 未声明的标识符(why \'cout\' is not a member of \'std\')

编译出现"cout": 未声明的标识符的错误

#include<iostream>
#include "stdafx.h"
#include<stdlib.h>

应把#include "stdafx.h"写在#include<iostream>的前面：

#include "stdafx.h"
#include<iostream>
#include<stdlib.h>