用的vc6.0编译器，函数及运算符的重载
#include <iostream>
using namespace std;
class String
{public:
String(){p=NULL;}
String()(char *str);
friend bool operator>(String &string1,String &string2);
friend bool operator<(String &string1,String &string2);
friend bool operator==(String &string1,String &string2);
void display();
private:
    char *p;
};
String::String(char *str)
{p=str;}

void String::display()
{cout<<p;}

bool operator>(String &string1,String &string2)
{if(strcmp(string1.p,string2.p)>0)
return true;
else
return false;
}
bool operator<(String &string1,String &string2)
{if(strcmp(string1.p,string2.p)<0)
return true;
else
return false;
}
bool operator==(String &string1,String &string2)
{if(strcmp(string2.p,string2.p)==0)
return true;
else
return false;
}
void compare(String &string1,String &string2)
{if(operator>(string1,string2)==1)
{string.display();cout<<">";string2.display();}
else
 if(operator<(string1,string2)==1)
 {string1.display();cout<<"<";string2.display();}
else
 if(operator==(string1,string2)==1)
 {string1.display();cout<<"=";string2.display();}
 cout<<endl;
}
int main()
{String string1("Hello"),string2("Book"),string3("Computer"),string4("Hello");
 compare(string1,string2);
 compare(string2,string3);
 compare(string1,string4);
 return 0;
}

什么叫function returns function?

谭浩强的c++程序设计(第3版)p309

你太有才了！这两处错误我竟然没发现！正解啊！

我打错代码了。和书本身无关！