Question

C++ ostream <<运算符重载 编译不通过

编译器为code::blocks
编译提示为：
|15|error: 'std::iostream& fuck::operator<<(std::iostream&, const fuck&)' must take exactly one argument|
||=== Build finished: 1 errors, 0 warnings ===|

#include<iostream>
using namespace std;
class fuck
{
int x;
public:
fuck(int x)
{
this->x=x;
}
friend iostream& operator<<(iostream & out,const fuck & f);
};
iostream& fuck::operator<<(iostream & out,const fuck & f)
{
return out<<f.x;
}
int main()
{

return 0;
}
大家把能编译通过的代码贴给我就可以了~

Answer 1

外面operator的定义把fuck：：去掉，因为它是fuck类的友元函数而不是成员函数。友元函数是公有函数。
iostream& operator<<(iostream & out,const fuck & f)
{
out<<f.x;
return out;
}

Answer 2

如下：

#include <iostream>
using namespace std;
class fuck{
int x;
public:
fuck(int x){ this->x=x; }
friend ostream& operator<<(ostream & out,const fuck & f);
// ostream而不是iostrem
};
ostream& operator<<(ostream & out,const fuck & f)
{
out<<f.x;
return out;
}
int main()
{
fuck f(1);
cout << f;
return 0;
}

Answer 3

好像是说 << 不能做成友元的重载，
只能是带一个参数的成员函数。