于达——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。

package example;


interface Shape {//定义接口 接口方法
    abstract double getArea();

}

package example;

class rectangle implements Shape {//长方形类
double chang;
double kuan;
rectangle(double chang,double kuan){
    this.chang=chang;
    this.kuan=kuan;
}

    public double getArea(){
    
        return chang*kuan;
    }

}
class zheng implements Shape{//正方形类
    double bian;
    double area;
    zheng (double bian){
        this.bian=bian;
    }
    public double getArea() {
        
        return area=bian*bian;
    }
}
class yuan implements Shape{//圆形类
    final double p=3.14;
    double banjing;
    yuan(double banjing){
        this.banjing=banjing;
    }
    public double getArea() {
        return p*banjing*banjing;
    }
}
class tixing implements Shape{//梯形类
    double shangdi;
    double xiadi;
    double gao;
    tixing(double shangdi,double xiadi,double gao){
        this.shangdi=shangdi;
        this.xiadi=xiadi;
        this.gao=gao;
    }
    public double getArea() {
        return (shangdi+xiadi)*gao/2;
    }
}
class sanjiao implements Shape{//三角形类
    double a;
    double b;
    double c;
    sanjiao(double a,double b,double c){
        this.a=a;
        this.b=b;
        this.c=c;
    }
    public double getArea() {
        double d =(a+b+c)/2;
        return Math.sqrt(d*(d-a)*(d-b)*(d-c));
    }
}
class zhuti{//柱体类
    Shape shape;
    double gao;
    zhuti(Shape shape,double gao){
        this.shape=shape;
        this.gao=gao;
    }
    void huandi(Shape shape) {//换底方法
        this.shape=shape;
    }
    double volume(){//求体积方法
        return shape.getArea()*gao;
    }
}

package example;
import java.util.*;


class works {//简单工厂类
    Shape shape=null;
    Scanner reader = new Scanner(System.in);
public Shape shape() {
    char z=reader.next().charAt(0);
        switch(z) {
        case'j':System.out.println("矩形体积是：");shape=new rectangle(3,4);break;
        case'z':System.out.println("正方形体积是：");shape=new zheng(5);break;
        case'y':System.out.println("圆形体积是：");shape=new yuan(5);break;
        case's':System.out.println("三角形体积是：");shape=new sanjiao(5,6,7);break;
        case't':System.out.println("梯形体积是：");shape=new tixing(5,6,7);break;
        }
        return shape;
}


}

package example;

public class js {//主类

    public static void main(String[] args) {//主方法
double gao=5;
works worker=new works();
System.out.println("请输入t/z/c/y/s");
for(;;) {//执行for循环，执行简单工厂里的switch，输入一个字母并输出对应柱体的体积。
    zhuti zt=new zhuti(worker.shape(),gao);
System.out.println(""+zt.volume());
}

    }

}

运行结果：