error C2065: 'string' : undeclared identifier

Question

#include<iostream.h>
#include<string>
//#include<vector>
//#include<iterator>
//#include<algorithm>
int main()
{
string str("hello world!");
cout<<str<<"\n";
for(int i=str.length()-1;i>=0;i++)
cout<<str[i];
cout<<endl;
return 0;
}
List_1.cpp(9) : error C2065: 'string' : undeclared identifier
F:\C\C++\C++练习\STRING类\List_1.cpp(9) : error C2146: syntax error : missing ';' before identifier 'str'
F:\C\C++\C++练习\STRING类\List_1.cpp(9) : error C2065: 'str' : undeclared identifier
F:\C\C++\C++练习\STRING类\List_1.cpp(11) : error C2228: left of '.length' must have class/struct/union type
F:\C\C++\C++练习\STRING类\List_1.cpp(12) : error C2109: subscript requires array or pointer type
执行 cl.exe 时出错.

Answer 1

#include <iostream.h>
#include <string>
改为
#include <iostream>
#include <string>
using namespace std;本回答被提问者和网友采纳

Answer 2

在#include <string>下面加上：
using namespace std;追问

还需要把#include改成#include
再加那个using namespace std;

Answer 3

应该是#include<string.h>

Answer 4

提示string这个类型不认识，未定义