11.6.cpp

这是C++的一部分练习程序!对初学者有一定的帮助作用。

#include <iostream.h>
#include <string.h>
class String
{
public:
	String()
	{  str=NULL;  }
	String(char *s)
	{  str=s;  }
	friend bool operator >(String &s1,String &s2);
	friend bool operator <(String &s1,String &s2);
	friend bool operator ==(String &s1,String &s2);
	void Print()
	{  cout<<str;  }
private:
	char *str;
};
bool operator >(String &s1,String &s2)
{
	if(strcmp(s1.str,s2.str)>0)
		return true;
	else
		return false;
}
bool operator <(String &s1,String &s2)
{
	if(strcmp(s1.str,s2.str)<0)
		return true;
	else
		return false;
}
bool operator ==(String &s1,String &s2)
{
	if(strcmp(s1.str,s2.str)==0)
		return true;
	else
		return false;
}
void compare(String &s1,String &s2)
{
	if(s1>s2)
	{
		s1.Print();
		cout<<'>';
		s2.Print();
	}
	else if(s1<s2)
	{
		s1.Print();
		cout<<'<';
		s2.Print();
	}
	else 
	{
		s1.Print();
		cout<<"==";
		s2.Print();
	}
	cout<<endl;
}
void main()
{
	String s1("continue"),s2("break"),s3("while"),s4("continue");
	compare(s1,s2);
	compare(s2,s3);
	compare(s1,s4);
}