定义一个圆类,要求:分别用成员函数和友元函数来求圆的面积和周长

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

classRecangle{private:intwidth;intlength;public:Recangle(){width=0;length=0;};Recangle(intw,inth){wi

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

可以的,在类内定义的函数被视为内联函数.在类内定义一般函数没什么要求,但是定义的是操作符重载的话,就有一定限制了.有些操作符的重载是不能再类内定义的.具体可参阅C++Primer.

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

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

publicclassStudent{Stringname,id;intage,english,math,chinese;Student(inta,intb,intc,intd,Stringe,Str

classTriangle{private:\x05doublea;\x05doubleb;\x05doublec;public:\x05Triangle():a(0),b(0),c(0){}\x05

#includeusingnamespacestd;classcat{public:cat();virtual~cat();public:floatweight;staticinthowmany

classComplex{public:Complex(){real=0;imag=0;}//定义结构函数Complex(doubler,doublei){real=r;imag=i;}//构造函数重

#includeusingnamespacestd;classClock{public:Clock(inth=0,intm=0,ints=0):hour(h),minute(m),second(s){

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

classcircle{public:circle(){radius=0;}circle(doubleradiuv){radius=radiuv;}voidgetparimeter(){parimet

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

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

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

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