定义计算圆面积的函数Area

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.

第一个空,函数需要返回一个double类型的值,因此填：returna;第二个空,需要对a=5用area函数,因此填：area(a)最后这是一个C语言的问题,如果在计算机分类上问应该很快就解决了吧.

classShape{public:virtualfloatarea()const{return0;}};classCircle{private:floatradius;public:floatare

classTrapezoid:publicShape{private:doubletop;doublebottom;doubleheight;public:Trapezoid(doublet,

#include"stdafx.h"#include#includeusingnamespacestd;classCShape{public:\x09virtualvoidArea()=0;\x09v

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

引入包类我还没有学,不好意思.希望对你有助.classCicle//定义圆类.{doublearea(doubler)//定义方法计算圆的面积.{return3.14*r*r;}}classTest5

我有个类似的,你看一下importjava.awt.*;importjava.applet.*;abstractclassShapes{protectedintx,y,k;protecteddoubl

Java的行不,C++的不记得了.publicclassCircle{privatestaticdoublePI=3.14privatedoubleradius;publicCircle(double

#includeclassCircle{public:Circle():radius(0){}Circle(doubler):radius(r){}constdoublearea()co

类似的问题,在知道里面不知道有多少.搜索一下.

publicinterfaceArea{\x05publicdoublecalculateArea();}publicclassMyRectangle{doublelength;doublewidth

#includeusingnamespacestd;#definePI3.14classPoint{public:\x09Point():m_x(0),m_y(0){}\x09Point(double

#include#includeclasslocation{private:floatx;floaty;floata;public:location(){x=0;y=0;}location(float

#includeusingnamespacestd;classCircle{public:Circle(doubler=0):radius(r){}doubleArea(){return3.14*ra

#definePI3.1415926#include#includeintmain(){doublea,b,c,d;doubles,S,e,m,p;scanf("%lf\n",&a);scanf("%

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

Console.WriteLine("请输入圆的半径");intr=int.Parse(Console.ReadLine());doublecircle=2*3.14*r;doublearea=3.1

publicinterfaceCircle{doublearea(doubler);}publicclassCircleImplimplementsCircle{publicdoublearea(do

//1#include<stdio.h>#define PI (3.1415)int main(void){    f