area.java

一个求圆

import java.lang.Math
public class Area{                          //定义了类Area_cir，作为外部类
      float l,s;
      public abstract class abc{                          //定义了接口abc
           public abstract float cir();
           public abstract float area();
           public abstract void output();
}
public class Zhix extends abc{            //定义了内部类Zhix，求解直线的周长和面积
           float x1,x2,y1,y2;
           public Zhix(float x,float y,float z,float w){
                  x1=x;
                  x2=y;
                  y1=z;
                  y2=w;
}
           public float cir(){
                  double d=(x1-x2)*(x1-x2);
                  double e=(y1-y2)*(y1-y2);
                  float l=Math.sqrt(d+e);
                  return l;}
           public float area(){
                  s=-1;
                  return s;
}
           public void output(){
                  System.out.println("the circle of the zhixian is:"+this.cir());
                  System.out.println("the area of the zhixian is :"+this.area());
}
}
      public class Sanjx extends abc {         //定义了内部类Sanjx，求解三角形的周长和面积
           float a,b,c,u;
           public Sanjx(float x,float y,float z){
                  a=x;
                  b=y;
                  c=z;
}
           public float cir(){
                  l=a+b+c;
                  return l;}
           public float area(){
                  u=l/2;
                  double k=u*(u-a)*(u-b)*(u-c);
                  float s=Math.sqrt(k);
                  return s;
}
           public void output(){
                  System.out.println("the circle of the sanjx is:"+this.cir());
                  System.out.println("the area of the sanjx is:"+this.area()); }
}
      public class Jux extends abc{                 //定义了内部类Jux，求解矩形的周长和面积
           float m,n;
           public Jux(float x,float y){
                  m=x;
                  n=y;
}
           public float cir(){
                  l=(m+n)*2;
                  return l;
                  }
           public float area(){
                  s=m*n;
                  return s;
}
           public void output(){
                  System.out.println("the circle of the juxing is:"+this.cir());
                  System.out.println("the area of the juxing is:"+this.area()); }
}
      public class Yuanx extends abc{       //定义了内部类Yuanx，求解圆形的周长和面积
           float r;
           final float PI=3.14;
           public Yuanx(float x){
                  r=x;
}
           public float cir(){
                  l=2*PI*r;
                  return l;}
           public float area(){
                  s=PI*r*r;
                  return s;
}
           public void output(){
                  System.out.println("the circle of the yuanxing is:"+this.cir());
                  System.out.println("the area is of the yuanxing:"+this.area()); }
}

    public Area(){
           Zhix a4=new Zhix(3,6,9,12);                //生成直线对象
           a4.output();
           Sanjx a1=new Sanjx(6,8,10);                //生成三角形对象
           a1.output();
           Jux a2=new Jux(7.6,9);                    //生成矩形对象
           a2.output();
           Yuanx a3=new Yuanx(9.3);                  //生成圆形对象
           a3.output();

}
   public static void main(String args[]){
           Area a=new Area();
}
}