#include <iostream>
#include <string>
using namespace std;
class String
{
public:
String(){p=NULL;}
String(char *str);
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;}
void main()
{String string1("hello"),string2("book");
cout<<(string1>string2)<<endl;}
如果你用的而是vc6，这应该是个别中文版的问题，就是友元有点问题，将运算符改为成员重载就可以了，程序中还有一点小错误，一并改正如下：
#include <iostream>
#include <cstring>
using namespace std;
class String
{
public:
String(){p=NULL;}
String(char *str);
bool operator>(String &string2);
void display();
private:
char *p;
};
String::String(char *str)
{p=str;}
void String::display()
{cout<<p;}
bool String::operator>(String &string2)
{if(strcmp(p,string2.p)>0)
return true;
else return false;}
void main()
{String string1("hello"),string2("book");
cout<<(string1>string2)<<endl;}来自：求助得到的回答
#include <iostream>
#include <cstring>
using namespace std;
class String
{
public:
String(){p=NULL;}
String(char *str);
bool operator>(String &string2);
void display();
private:
char *p;
};
String::String(char *str)
{p=str;}
void String::display()
{cout<<p;}
bool String::operator>(String &string2)
{if(strcmp(p,string2.p)>0)
return true;
else return false;}
void main()
{String string1("hello"),string2("book");
cout<<(string1>string2)<<endl;}来自：求助得到的回答
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