第二题

#include <iostream> 
using namespace std; 
class Date 
 {public: 
   Date(int,int,int); 
   Date(int,int); 
   Date(int); 
   Date(); 
   void display(); 
  private: 
   int month; 
   int day; 
   int year; 
 }; 
  
Date::Date(int m,int d,int y):month(m),day(d),year(y) 
 { } 
  
Date::Date(int m,int d):month(m),day(d) 
 {year=2005;} 
  
Date::Date(int m):month(m) 
 {day=1; 
  year=2005; 
 } 
  
Date::Date() 
 {month=1; 
  day=1; 
  year=2005; 
 }  
void Date::display() 
 {cout<<month<<"/"<<day<<"/"<<year<<endl;} 
  
int main() 
{ 
 Date d1(10,13,2005); 
 Date d2(12,30); 
 Date d3(10); 
 Date d4; 
 d1.display(); 
 d2.display(); 
 d3.display(); 
 d4.display(); 
 return 0; 
 }