武汉理工大学java课内实验一（使用接口实现）.zip

package 接口; import java.util.Scanner; import java.text.DecimalFormat; public class AreaInterface { public static void main(String[] args) { Scanner scan = new Scanner(System.in); double radius = scan.nextDouble(); double high = scan.nextDouble(); double upperBase = scan.nextDouble(); double lowerBase = scan.nextDouble(); Circular circular = new Circular(radius);//创建圆形对象 circular.area(); circular.girth(); Trapezoid trapezoid = new Trapezoid(high, upperBase, lowerBase);//创建梯形对象 trapezoid.area(); scan.close(); } } /** * Area接口 */ interface Area{ double PI = 3.14; void area(); } /** * Girth接口 */ interface Girth{ void girth(); } /** * 接口的多继承，需实现接口的所有方法 */ class Circular implements Area,Girth{ private final double radius; public Circular(double radius){ this.radius = radius; } public void area(){ double circularArea; circularArea = PI * radius * radius; System.out.println("圆的面积为：" + new DecimalFormat("#.000").format(circularArea)); } public void girth(){ double circularGirth; circularGirth = 2 * PI * radius; System.out.println("圆的周长为："+ new DecimalFormat("#.000").format(circularGirth)); } } /** * 实现Area接口的area（）方法 */ class Trapezoid implements Area{ private final double high; private final double upperBase; private final double lowerBase; public Trapezoid (double high,double upperBase,double lowerBase){ this.high = high; this.upperBase = upperBase; this.lowerBase = lowerBase; } public void area(){ double trapezoidArea; trapezoidArea = (upperBase + lowerBase) * high / 2; System.out.println("梯形的面积为：" + new DecimalFormat("#.000").format(trapezoidArea)); } }