C++构造函数与析构函数的解析

class Time
{
   public : //声明为公用成员
   hour;
   minute;
   sec;
};
Time t1={14,56,30};  //将t1初始化为14:56:30

#include <iostream>
using namespace std;
class Time
{
   public :
   Time( )
   {
      hour=0;
      minute=0;
      sec=0;
   }
   void set_time( );
   void show_time( );
   private :
   int hour;
   int minute;
   int sec;
};
void Time::set_time( )
{
   cin>>hour;
   cin>>minute;
   cin>>sec;
}
void Time::show_time( )
{
   cout<<hour<<":"<<minute<<":"<<sec<<endl;
}
int main( )
{
   Time t1;
   t1.set_time( );
   t1.show_time( );
   Time t2;
   t2.show_time( );
   return 0;
}

Time::Time( ) //在类外定义构造成员函数，要加上类名Time和域限定符“::”
{
   hour=0;
   minute=0;
   sec=0;
}

#include<string>
#include<iostream>
using namespace std;
class Student //声明Student类
{
   public :
   Student(int n,string nam,char s ) //定义构造函数
   {
      num=n;
      name=nam;
      sex=s;
      cout<<"Constructor called."<<endl; //输出有关信息
   }
   ~Student( ) //定义析构函数
   {
      cout<<"Destructor called. The num is "<<num<<"."<<endl;
   } //输出有关信息
   void display( ) //定义成员函数
   {
      cout<<"num: "<<num<<endl;
      cout<<"name: "<<name<<endl;
      cout<<"sex: "<<sex<<endl<<endl;
   }
   private :
   int num;
   string name;
   char sex;
};
int main( )
{
   Student stud1(10010,"Wang_li",‘f‘); //建立对象stud1
   stud1.display( ); //输出学生1的数据
   Student stud2(10011,"Zhang_fun",‘m‘); //定义对象stud2
   stud2.display( ); //输出学生2的数据
   return 0;
}