课后练习5: package five_c5; public abstract class Printer { public abstract void print(); } package five_c5; public class LaserPrinter extends Printer{ public void print() { System.out.println("激光打印"); } public void test(Printer test) { System.out.println("哈哈哈哈"); } } package five_c5; public class InkpetPrinter extends Printer { public void print() { System.out.println("喷墨打印"); } } package five_c5; public class DotMatrixPrinter extends Printer{ public void print() { System.out.println("针式打印"); } } package five_c5; public class Test { public static void main(String[] args) { //Printer printer = new DotMatrixPrinter(); //Printer printer = new InkperPrinter(); Printer printer = new LaserPrinter(); printer.print(); Printer test = new LaserPrinter(); if(test instanceof LaserPrinter) { LaserPrinter p = (LaserPrinter)test; p.test(test); } } } 课后练习6: package five_c6; public abstract class Niu { public abstract void eat(); } package five_c6; public class Wang extends Niu { public void eat() { System.out.println("王小强喜欢吃四川菜"); } public void riot() { System.out.println("王小强练太极拳"); } } package five_c6; public class John extends Niu { public void eat() { System.out.println("约翰喜欢吃披萨"); } public void ball() { System.out.println("约翰打橄榄球"); } } package five_c6; public class Test { public static void main(String[] args) { Niu niu = new Wang(); niu.eat(); if(niu instanceof John) { John john = (John)niu; john.ball(); }else if(niu instanceof Wang) { Wang wang = (Wang)niu; wang.riot(); } } }
面向对象 第5章
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转载自blog.csdn.net/lsxdbd/article/details/80171551
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