静态数据成员应用

#include <iostream>
#include<cstdlib>
using namespace std;
class Time
{
public:
Time(int=0,int=0,int=0);
void show_time();
void add_seconds(int );
void add_minutes(int );
void add_hours(int );
static void change24();
static void changefrom0();
private:
static bool is_24;
static bool from0;
int hour;
int minute;
int sec;
};
bool Time::is_24=true;
bool Time::from0=false;
Time::Time(int _hour,int _minute,int _sec)
{
hour=_hour;
minute=_minute;
sec=_sec;
}
void Time::show_time()
{

int _hour;
if(is_24)
_hour=hour;
else
_hour=hour%12;
if (_hour<10&&from0) cout<<'0';
cout<<_hour<<':';
if(minute<10&&from0) cout<<'0';
cout<<minute<<':';
if(sec<10&&from0) cout<<'0';
cout<<sec;
if(!is_24)

if (hour>12)
cout<<" pm";
else
cout<<" am";
cout<<endl;
}

void Time::add_seconds(int n)
{
sec=sec+n;
if(sec>=60)
{
sec=sec%60;
minute=minute+sec/60;
if(minute>=60)
{
minute=minute%60;
hour=hour+minute/60;
}
if(hour>=24)
hour=hour%24;
}
}
void Time::add_minutes(int n)
{
minute=minute+n;
if(minute>=60)
{
minute=minute%60;
hour=hour+minute/60;
}
if(hour>=24)
hour=hour%24;

}
void Time::add_hours(int n)
{
hour=hour+n;
if(hour>=24)
hour=hour%24;
}
void Time::change24()
{
is_24=!is_24;
}
void Time::changefrom0()
{
from0=!from0;
}
int main()
{
Time t1(23,14,25),t2(8,45,6);
cout<<"24时制, 不前导："<<endl;
cout<<"    t1是：";
t1.show_time();
cout<<"    t2是：";
t2.show_time();
t1.add_hours(10);
t2.add_hours(10);
Time::changefrom0();
cout<<"10小时后, 切换是否前导："<<endl;
cout<<"    t1是：";
t1.show_time();
cout<<"    t2是：";
t2.show_time();
t1.change24();
cout<<"换一种制式："<<endl;
cout<<"    t1是：";
t1.show_time();
cout<<"    t2是：";
t2.show_time();
system("pause");
return 0;
}