类 class

#include <stdio.h>
#include <iostream>
#include <stdlib.h>
using namespace std;
class rectangle
{
    private:
    	double width,heigth;//˽ÓÐÊý¾Ý,Ö»Äܱ»ÄÚ²¿º¯Êýµ÷Óà 
    public:
    	rectangle():width(1.0),heigth(1.0){}//¹¹Ô캯Êý£¬È±Ê¡µÄ 
		rectangle(int width,int heigth):width(width),heigth(heigth){}//¹¹Ô캯Êý 
		double getarea()//ÐÐΪ 
		{
			double sum=width*heigth;
			return sum;
		}
		double getperimeter()//ÐÐΪ 
		{
			double c=(width+heigth)*2;
			return c;
		}
		~rectangle()//Îö¹¹º¯Êý£¬³ÌÐò×Ô¶¯µ÷Ó㬾ßÌåʲôʱºò£¬¿ÉÒÔÉÏÍø²é 
		{
			cout<<"end"<<endl;
		} 
};

int main()
{
	double a,b;
	cin>>a>>b;
	rectangle rect(a,b);
	double sum=rect.getarea();
	double c=rect.getperimeter();
	printf("area=%lf
",sum);
	printf("perimeter=%lf
",c);
	return 0;
}

/*
a=1,b=1;
Êä³ö£º
area=1.000000
perimeter=4.000000
end
*/

　　

#include <stdio.h>
#include <iostream>
#include <stdlib.h>
using namespace std;
class rectangle
{
    private:
    	double width,heigth;//私有数据,只能被内部函数调用 
    public:
    	rectangle();//只把函数名称先申明 
		rectangle(double a,double b); 
		double getarea();
		double getperimeter();
		~rectangle();
};

rectangle::rectangle()//具体函数，构造函数和析构函数最特别，没有返回值，且：：前后都是类名 
{
	width=1.0;
	heigth=1.0;
}

rectangle::rectangle(double a,double b)//构造函数的重载，每个函数都可以重载 
{
	width=a;
	heigth=b;
}

double rectangle::getarea()//其他行为函数，返回值+类名+：：+函数名，函数体与一般函数相同 
{
	double sum=width*heigth;
	return sum;
}

double rectangle::getperimeter()
{
	double c=(width+heigth)*2;
	return c;
}

rectangle::~rectangle()//析构函数 
{
	cout<<"end"<<endl;
}

int main()
{
	double a,b;
	cin>>a>>b;
	rectangle rect(a,b);
	double sum=rect.getarea();
	double c=rect.getperimeter();
	printf("area=%lf
",sum);
	printf("perimeter=%lf
",c);
	return 0;
}

/*
a=1,b=1;
输出：
area=1.000000
perimeter=4.000000
end
*/