#include<iostream>
#ifndef STRNGBAD H
#define STRNGBAD H
class StringBad
{
private:
char *str;
int len;
static int num_strings;
public:
StringBad(char *str); //constructor
StringBad(); //default constructor
~StringBad();
friend std::ostream & operator <<(std::ostream & os , const StringBad & st);
};
#endif
求大神解释一下这一句:
friend std::ostream & operator <<(std::ostream & os , const StringBad & st);
那个&运算符是什么意思?以及括号中的参量?