C++ “字符串”未声明
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`string' undeclared
提问by amartin94
Writing my first program, and my using namespace std;statement won't work. When I build the program I'm getting thrown this error:
编写我的第一个程序，我的using namespace std;语句不起作用。当我构建程序时，我抛出了这个错误：
C:\Users\p6735a\Desktop\Project\game.cpp: In function `int main(int, char *)':
C:\Users\p6735a\Desktop\Project\game.cpp:6: `string' undeclared (first use this function)
C:\Users\p6735a\Desktop\Project\game.cpp:6: (Each undeclared identifier is reported only once
C:\Users\p6735a\Desktop\Project\game.cpp:6: for each function it appears in.)
C:\Users\p6735a\Desktop\Project\game.cpp:6: parse error before `;'
[Finished in 0.1s with exit code 1]
Here's the code:
这是代码：
#include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
string input;
int hp;
cout << "You see a man. Would you like to kill him?\n1. Yes\n2. No" << endl;
//cin >> input;
}
回答by 0x499602D2
You need to include the string header:
您需要包含字符串标题：
#include <string>
But why have a using namespace stddeclaration at all? Simply use the objects individually:
但是为什么要using namespace std声明呢？只需单独使用对象：
using std::cout;
using std::string;
回答by taocp
Add
添加
#include <string>
to your includes since stringis from <string>header.
到您的包含，因为string来自<string>标题。
Meanwhile, it is bad practice to use using namespace std(see Why using namespace std is considered a bad practice), you'd better use:
同时，使用是不好的做法using namespace std（请参阅为什么使用命名空间 std 被认为是不好的做法），您最好使用：
std::string input
std::cout, std::endl
instead.
反而。
回答by SilverFang
In Visual Studio you need to have the new #include "pch.h".
在 Visual Studio 中，您需要拥有新的#include "pch.h".
