定义一个圆类

usingSystem;usingSystem.Collections.Generic;usingSystem.Text;namespaceConsoleApplication1{publicclas

圆的特点是什么呢?很简单：平面上,从中心到圆周上任意一点之距离相等.那么,你可以画一张图：建立平面直角坐标系xOy,为方便理解,先取原点为圆心作一个圆,并任意连接一条半径OA=r.设A（x,y）.如此

#include"stdio.h"constdoubleP=3.14;classCircle{public:virtualdoubleArea();voidR(doubles);doublegetr(

周长：形成整个圆的那条曲线的长度叫圆的周长.面积：组成员的那条曲线中的面积,就是圆的面积.

namespaceEX1_4{publicclassshape{publicdoublePI=3.14;}publicclassRectangle:shape{publicintx,y,s,l;pub

classcircle{public:circle(doubleradius):_radius(radius){}~circle(void);private:double_radius;public:

#include <stdio.h>#include <stdlib.h>class Point{private: int _

我给你举一个例子吧.classCargo{private://定义成员变量floatweight;floatcharge;public:Cargo(){};//构造函数Cargo(){};//析构函数

classCircle{public:Circle(intnr){r=nr;}Circle(){}public:intr;intArea(){return3.14*r*r;}};classB{publ

以下程序,直接拿去交作业吧,都测试过了.//圆周长面积#include#definepi3.14159classcircle{public:voidsetRadius(){std::cout

朋友这个是C++的吧!classPoint{private:intm_nX;intm_nY;public://...}classCircle:publicPoint{private:intm_nR;p

publicclassTest{\x05publicstaticvoidmain(String[]args){\x05\x05Rectangler=newRectangle(5,4);\x05\x05

把这三个类分别放到三个.java文件中,然后编译运行即可.publicclassCircle{privatedoubler;publicCircle(doubler){this.r=r;}public

usingSystem;classRectangle{privateintwidth;privateintheight;publicRectangle(intw,inth){width=w;heigh

这个是pascal的做法programabcconstpai=3.14varR,Area:real;beginwriteln("pleaseinputanumberforr:");readln(r);

//complex类#include#includeclasscomplex{doublereal,imag;public:complex(){real=5;imag=5;}//缺省构造函数compl

classa{publcstatevoidb(){}}

测试通过（编译器为gcc-3.4.5):#include#includeintmain(){classBook{public:longnumber;floatprice;char*bookname;v

无数个,类名必须不一样,public的只能有一个.而且必须与文件名一致.

1)Youdon'tneedamemberfunction2)Youdon'tevenneedamembervariable3)Aclasscanbeempty再问：ok，Iunderstand，th