C++编译错误no operator defined which takes a right-hand operand of type 'class std::basic_string

Question

出现这个错误，求解释，代码在下面no operator defined which takes a right-hand operand of type 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' (or there is no acceptable
conversion)

#include <iostream.h>

#include <string>
int main()
{
using std:: string;
string word;
while(cin>>word)
cout<<word<<endl;
return 0 ;
}

Answer 1

说明是字符串不能用这个输入符号。另外这句没有明白是什么意思using std:: string;如果是想命名空间也不是这样，更何况，string是属于C++的关键字，不能用，应该是：using namespace std;吧

Answer 2

#include <iostream> // 不要加.h
#include <string>
int main()
{
using std::string;
using std::cin;// 如果不想用using namespace std，那么每个名字都要using
using std::cout;
using std::endl;

string word;
while(std::cin>>word)
std::cout<<word<<endl;
return 0 ;
}

Answer 3

去掉<iostream.h>中的h