请问要怎么解决 我有include<iostream>了啊

Question

错误 5 error C2061: 语法错误: 标识符“istream” g:\编程\c++\类模板6\类模板6\t_counter.h 20 类模板6

#ifndef T_Counter_H
#define T_Counter_H

#include
template
class T_counter
{
private:
T i;
public:
T_counter( T k=0):i(k){}

template <typename S>
friend T_counter<S> operator+(T_counter<S>&a,T_counter<S> &b);
template <typename T>
friend T_counter<T> operator-(T_counter<T>&a,T_counter<T> &b);
template <typename T>
friend T_counter<T> operator*(T_counter<T>&a,T_counter<T> &b);
template <typename S>
friend istream & operator>>(istream &input,T_counter<S> &a);
template <typename S>
friend ostream &operator<<(istream &output,T_counter<S> &a);

};

#endif

#include"T_counter.h"
template
T_counter operator+(T_counter&a,T_counter&b)
{
T j=a.i+b.i;
return T_counter(j);
}

template
T_counter operator-(T_counter&a,T_counter&b)
{
T j=a.i-b.i;
return T_counter(j);
}

template
T_counter operator*(T_counter&a,T_counter&b)
{
T j=a.i*b.i;
return T_counter(j);
}

template
istream &operator >>(istream &input, T_counter & a)
{
input>>a.i;
return input;
}

template
ostream &operator<<(istream &output,T_counter&a)
{
input>>a.i;
return output;
}

Answer 1

#include <iostream>
using namespace std;