C++类和对象实例解析（二）

void getdate();          //取日期值，格式为“year-month-day”
int getyear();          //取年份
int getmonth();         //取月份
int getday();          //取日期
void setdate(int y,int m,int d);    //设置日期值
程序代码如下：
#include <iostream>
using namespace std;
class date
{
public:
 void getdate();
 int getyear();
 int getmonth();
 int getday();
 void setdate(int y,int m,int d);
private:
 int year,month,day;
};
int date::getyear(){ return year; }
int date::getmonth(){ return month; }
int date::getday(){ return day; }
void date::getdate()
{ cout<<"today is:"<<year<<"-"<<month<<"-"<<day<<endl; }
void date::setdate(int y,int m,int d)
{ year=y; month=m; day=d;  }
int main()
{
 date d;
 d.setdate(2011,2,1);
 cout<<"year="<<d.getyear()<<endl;
 cout<<"month="<<d.getmonth()<<endl;
 cout<<"day="<<d.getday()<<endl;
 d.getdate();
 return 0;
}

#include <iostream>
using namespace std;
class date
{
public:
 date(int y=0,int m=0,int d=0)
 { year=y; month=m; day=d; }
 date(date &d)
 { year=d.year; month=d.month; day=d.day; }
 void getdate()
 { cout<<"today is:"<<year<<"-"<<month<<"-"<<day<<endl; }
 int getyear() { return year; }
 int getmonth() { return month; }
 int getday() { return day; }
private:
 int year,month,day;
};

int main()
{
 date d1(2011,2,1),d2,d3(d1);
 d1.getdate();
 d2.getdate();
 d3.getdate();
 return 0;
}

#include <iostream>
using namespace std;
#define N 10
class array
{
public:
 void input();
 void output();
 int max();
 int min();
 int sum();
 float average();
private:
 int a[N],maxnumber,minnumber,sumnumber;
 float avenumber;
};
void array::input()
{
 int i=0;
 cout<<"Please input "<<N<<" numbers:"<<endl;
 for(i=0;i<N;i++)
 {
 cout<<"a["<<i<<"]=";
 cin>>a[i];
 }
}
void array::output()
{
 int i=0;
 cout<<"array a is:"<<endl;
 for(i=0;i<N;i++)
 cout<<a[i]<<" ";
 cout<<endl;
}
int array::max()
{
 int i;
 maxnumber=a[0];
 for(i=1;i<N;i++)
 if(maxnumber<a[i])
  maxnumber=a[i];
 return maxnumber;
}
int array::min()
{
 int i;
 minnumber=a[0];
 for(i=1;i<N;i++)
 if(minnumber>a[i])
  minnumber=a[i];
 return minnumber;
}
int array::sum()
{
 int i;
 sumnumber=a[0];
 for(i=1;i<N;i++)
 sumnumber+=a[i];
 return sumnumber;
}
float array::average()
{
 float ave=static_cast<float>(sumnumber/N);
 return ave;
}
int main()
{
 array a;
 a.input();
 a.output();
 cout<<"The max number is "<<a.max()<<endl;
 cout<<"The min number is "<<a.min()<<endl;
 cout<<"The sum number is "<<a.sum()<<endl;
 cout<<"The average number is"<<a.average()<<endl;
  return 0;
}

#include <iostream>
#include <string>
using namespace std;
class Cat
{
public:
 Cat(string c="red",float w=1,int a=1);
 string get_color();
 float get_weight();
 int get_age();
 void display();
private:
 string color;
 float weight;
 int age;
};
Cat::Cat(string c,float w,int a)
{
 color=c;
 weight=w;
 age=a;
}
string Cat::get_color()
{
 return color;
}
float Cat::get_weight()
{
 return weight;
}
int Cat::get_age()
{
 return age;
}
void Cat::display()
{
 cout<<"The color of this cat is "<<get_color()<<endl;
 cout<<"The weight of this cat is "<<get_weight()<<endl;
 cout<<"The age of this cat is "<<get_age()<<endl;
}
int main()
{
 Cat c1,c2("yellow",1,2);
 cout<<"c1 is:"<<endl;
 c1.display();
 cout<<"c2 is:"<<endl;
 c2.display();
 return 0;
}