定义一个圆类,它含有半径数据成员,求面积和设置半径的成员函数

classscore{privatedoubleenglish;publicvoidsetScore(doubleenglish){this.english=english;}publicvoidpr

classCircle{\x09privatedoubler;\x09publicvoidsetR(doubler)\x09{\x09\x09this.r=r;\x09}\x09publicdoubl

#include#includeusingstd::cout;usingstd::cin;usingstd::endl;usingstd::string;classBook{public:Book(s

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

#includeusingnamespacestd;classcircle{private:doubleradius;public:circle(doubler=0.0);voidinput();do

#includeusingnamespacestd;constdoublepi=3.14;//Point类,派生出Rectangle类和Circle类,计算各派生类对象的面积Area（）.templa

classBox{doublelenth=0;doubleheight=0;doublewidth=0;publicdoublevolume(){returnlenth*height*width;}p

用什么语言编?

classcircle{public:circle(floatr=0){this->r=r;}floatarea();{return3.14*r*r;}private:floatr;};再问：再问：为

#include#definePI3.14159classCircle{private:floatradius,girth,area;public:Circle(floatr=0);//构造函数（以半

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

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

在此基础上派生出矩形类CRectangle和圆类CCircle.//矩形类包括左上角坐标、长和宽等数据成员及相关的成员函数（如计算面积、周长、显示矩形的属性值等）.//圆类包括圆心坐标、半径等数据成员

#include#includeusingnamespacestd;classCircle{public:\x05Circle(){}\x05Circle(Circle&c)\x05{\x05\x05

classCircle{intr,c,s;c=circle(r);s=square(r);}intcircle(intr){intc;c=2*3.1415926*r;return(c);}intsqu

classa{publcstatevoidb(){}}

#includeclasscircle{private:intr;public:voidinput(){cout

#include#definePI3.14159usingnamespacestd;classcircle{private:doubleRadius;public:voidjiandan();};vo

1a2a3d

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