第九次作业

 题目： 利用接口和接口回调，实现简单工厂模式，当输入不同的字符，代表相应图形时，利用工厂类获得图形对象，再计算以该图形为底的柱体体积。

class juxing implements Shape{//定义矩形类并实现接口，求面积
    double chang;
    double kuan;
    double mianji;
    juxing(double chang,double kuan){
        this.chang=chang;
        this.kuan=kuan;
        }    
    public double getmianji() {
        return mianji=chang*kuan;
    }
}

class zfx implements Shape{//定义正方形类并实现接口，求面积
    double bian;
    zfx(double bian){
    this.bian=bian;
}
    public double getmianji(){
    return bian*bian;
    }
}

class sjx implements Shape{//定义三角形类并实现接口，求面积
    double a;
    double b;
    double c;
    sjx(double a,double b,double c){
        this.a=a;
        this.b=b;
        this.c=c;
    }    
    public double getmianji() {
        double d= (a+b+c)/2;
        return Math.sqrt(d*(d-a)*(d-b)*(d-c));
    }
}

class yuanxing implements Shape{//定义圆形类并实现接口，求面积
    double r;
    yuanxing(double r){
        this.r=r;
    }
    public double getmianji() {
        return Math.PI*r*r;
    }
}

 class tixing implements Shape{//定义梯形类并实现接口，求面积
     double sd;
     double xd;
     double gao;
     tixing(double sd,double xd,double gao){
         this.gao=gao;
         this.sd=sd;
         this.xd=xd;
     }
     public double getmianji() {
         return (sd+xd)*gao/2;
     }
 } 

class zhuti{//定义柱体类，创建换底方法和球体积方法
    Shape shape;
    double gao;
    zhuti(Shape shape,double gao){
        this.shape=shape;
        this.gao=gao;
    }
    void huandi(Shape shape) {
        this.shape=shape;
    }
    double tiji() {
        return shape.getmianji()*gao;
    }
}

interface Shape{//定义接口，接口方法
    abstract double getmianji();
} 

class gc {//创建工厂类
    Shape shape=null;
    Scanner reader =new Scanner(System.in);
    
        public Shape shape(){
            char q=reader.next().charAt(0);
            switch(q){
            case 'j': System.out.println("矩形面积");shape = new juxing(5,2); break;
            case 'z': System.out.println("正方形面积");shape = new zfx(6); break;
            case 's': System.out.println("三角形面积");shape =new sjx(1,4,2); break;    
            case 'y': System.out.println("圆形面积");shape = new yuanxing(2); break;
            case 't': System.out.println("梯形面积");shape = new tixing(1,2,5); break;   
            }
            return shape;
        }
        
}

//主类

public class zz {private static boolean ture;

public static void main(String[] args) {

// TODO Auto-generated method stub
double gao=2;
gc gc1=new gc();
for(;;){
zhuti zhuti1=new zhuti(gc1.shape(), gao);
System.out.println(zhuti1.tiji());
}
}
}

测试结果：