摘要：
abstract class A{public abstract void f(int x);public abstract void g(int x,int y);public abstract void h(double x);}class Length extends A{public void f(int x){System.out.println("这个长方体的长为12。");}public void g(int x,int y){}public void h(double x){}}class Width extends A{public void g(int 阅读全文
摘要：
abstract class Geometry{public abstract double getArea();}class Pillar{Geometry bottom;double height;Pillar(Geometry bottom,double height){this.bottom=bottom;this.height=height;}void changeBottom(Geometry bottom){this.bottom=bottom;}public double getVolume(){return bottom.getArea()*height;}}class La 阅读全文
摘要：
class Animal{void cry(){}}class Dog extends Animal{void cry(){System.out.println("Wang!Wang!...");}}class Cat extends Animal{void cry(){System.out.println("miao~~~~miao~~~~");}}public class Example5_9{public static void main(String args[]){Animal animal;animal=new Dog();animal.cr 阅读全文
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class A{double n;int m;void f(){System.out.printf("子类继承方法f(),n=%f,m=%d\n",n,m);}void g(){System.out.printf("你好,n=%f,m=%d\n",n,m);}}class B extends A{int n=12;void g(){System.out.printf("子类重写方法g(),n=%d,m=%d\n",n,m);}void cry(){System.out.printf("子类新增的方法,n=%d,m=%d\n& 阅读全文
摘要：
class A{int x,y;A(){x=100;y=200;}A(int x,int y){this.x=x;this.y=y;}}class B extends A{int z;B(int x,int y){super(x,y);z=300;}B(){super();z=800;}public void f(){System.out.printf("x=%d,y=%d,z=%d\n",x,y,z);}}public class Example5_6{public static void main(String args[]){B b1=new B(10,20);b1. 阅读全文
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class A{protected double x=8.0,y=0.888888;public void speak(){System.out.println("我喜欢ＮＢＡ");}public void cry(){y=x+y;System.out.printf("y=%f\n",y);}}class B extends A{int y=100,z;public void speak(){z=2*y;System.out.println("I love This Game");System.out.printf("y=% 阅读全文
摘要：
class A{public double y=11.456789;public void f(){y=y+1;System.out.printf("y是double型的变量，y=%f\n",y);}}class B extends A{int y=0;public void g(){y=y+100;System.out.printf("y是int型的变量,y=%d\n",y);}}class Example5_3{public static void main(String args[]){B b=new B();b.y=200;b.g();b.f() 阅读全文
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class Father{private int moneyDollar=300;int moneyHK=200;int add(int x,int y){return x+y;}}class Son extends Father{int moneyRMB=800;public void changMoneyHK(int x){moneyHK=x;}public void changMoneyRMB(int x){moneyRMB=x;}int subs(int x,int y){return x-y;}}class GrandSon extends Son{int multi(int x,i 阅读全文
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public class Example4_18{public static void main(String args[]){char a[]={'a','b','c','D','E','F'};for(int i=0;i<a.length;i++){if(Character.isLowerCase(a[i])){a[i]=Character.toUpperCase(a[i]);}else if(Character.isUpperCase(a[i])){a[i]=Character.toLo 阅读全文
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public class Example4_15{private int money;Example4_15(){money=2000;}private int getMoney(){return money;}public static void main(String args[]){Example4_15 exa=new Example4_15();exa.money=3000;int m=exa.getMoney();System.out.println("money="+m);}}class Employee{private double salary=1800; 阅读全文