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标 题Re: [问题]关於多形和超载 程式码问题
发信站无名小站 (Tue May 23 04:17:14 2006)
转信站ptt!ctu-reader!Spring!feeder.seed.net.tw!news.ntu!mars.scc.ntnu!ctu-pe
※ 引述《cscfish (双栖动物)》之铭言：
> ※ 引述《cscfish (双栖动物)》之铭言：
> > 就是为啥我计算出的数字都会是0 是哪要改吗
> > 还有说要用多形和超载 那应该超载已经合多型条件了吧
> > 如果不合条件 那要怎麽改才可以呢
> > 因为getarea() 同时有计triangle circle rectangle的不同功能(多形)
> > class shape {
> > private double area,circum;
> > shape(double a,double b)
> > {
> > this.area=a;
> > this.circum=b;
> > }
> > public double getarea(){return area;}
> > double getcircum(){return circum;}
> > }
> > =====================================================
> > class circle extends shape {
> > private double r;
> > circle(double r)
> > {super(r,r);}
> > public double getarea(){return 3.14*r*r;}
> > public double getcircum(){return 6.28*r;};
> > }
> > =====================================================
> > class rectangle extends shape{
> > private double x,y;
> > rectangle(double x,double y)
> > {super(x,y);}
> > public double getarea(){return x*y;}
> > public double getcircum(){return 2*x+2*y;};
> > }
> > =====================================================
> > class triangle extends shape {
> > double s,t;
> > triangle(double s,double t)
> > { super(s,t);}
> > public double getarea(){return 0.5*s*t;}
> > public double getcircum(){return 3*s;};
> > }
> > =====================================================
> > public class calculate {
> > public static void main(String args[]){
> > circle cir=new circle(3);
> > triangle tri=new triangle(3,3);
> > rectangle rec=new rectangle(3,3);
> > System.out.print("\n" +cir.getarea());
> > System.out.print("\n" +cir.getcircum());
> > System.out.print("\n" +tri.getarea());
> > System.out.print("\n" +tri.getcircum());
> > System.out.print("\n" +rec.getarea());
> > System.out.print("\n" +rec.getcircum());
> > }
> > }
接着我要加一功能就是随便选一个图形 在计算其面积
我改这样不行 不知哪位大大可以在帮指点一下
class calculate {
public static void main(String args[]){
System.out.print("input integer of n");
int n=Integer.parseInt(keyin.readLine());//读取输入并存取n变数
//int circle=1,rectangle=2,triangle=3;
int create(n)
{
switch(n)
{
case 1:
System.out.print("\n" +cir.getarea(3));
System.out.print("\n" +cir.getcircum(3));
case 2:
System.out.print("\n" +tri.getarea(3,3));
System.out.print("\n" +tri.getcircum(3,3));
case 3:
System.out.print("\n" +rec.getarea(3,3));
System.out.print("\n" +rec.getcircum(3,3));
}
}
}
}
--
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