Java程序设计基础教程-杨佩理(源程序PDF课件

1、Java程序设计基础教程-杨佩理（源程序&PDF课件）例4-1class Abcstatic int num = 0;void count()num +;System.out.println(This is object + num);public static void main(String args)Abc a = new Abc();Abc b = new Abc();Abc c = new Abc();a.count();b.count();c.count();System.out.println(Abc.num);例4-2class Circledouble r;double ge

2、tL()return 2 * Math.PI * r; /Math.PI为圆周率double getS()return Math.PI * r * r;例4-3class MyCalstatic int getSum(int n)int sum=0;for(int i=1;i=n;i+)sum += i;return sum;static long getFac(int n)long fac=1;for(int i=1;i=n; i+)fac *= i;return fac;class Testpublic static void main(String aa) System.out.prin

3、tln(MyCal.getSum(100)+t+MyCal.getFac(10); 例4-4class Personint sex;int salary;void employed()System.out.print(Work state:);if (salary=0) System.out.println(no job);else System.out.println(job);class Testpublic static void main(String aa)Person ps=new Person();ps.salary=300;ps.employed();ps.salary=0;p

4、s.employed();例4-5class ReferenceTestpublic static void main(String args)Person p1 = new Person(); /设对象为A，p1指向APerson p2 = new Person(); /设对象为B，p2指向Bp1.salary = 1;p2.salary = 2;System.out.println(p1.salary+t+p2.salary);p1 = p2; / p1重定向，也指向了p2指向的BSystem.out.println(p1.salary + t + p2.salary);p1.salary

5、 = 8;System.out.println(p1.salary + t + p2.salary);例4-6class Starstatic void print(char c,int n)for(int i=0; in; i+)System.out.print(c);public static void main(String args) for(int i=0;i5;i+) print( , 10-i); /输出10-i个空格 print(*,2*i + 1); /输出2i+1个星号 System.out.println(); 例4-7class TestCirclepublic sta

6、tic void main(String args)Circle cc = new Circle();cc.r = 3.5; System.out.println(cc.getL() + tt + cc.getS(); 例4-8class TestOLint x;void func()System.out.println(no arg);String func(int i)return arg is + i;void func(String s)System.out.println(s);public static void main(String a)TestOL c = new TestO

7、L();c.func();c.func(c.func(100);例4-9class TestOL1void func(double x)System.out.println(x+ is double);void func(int x)System.out.println(x+ is int);public static void main(String a)TestOL1 c=new TestOL1();c.func(1); /将调用void func(int x)c.func(2.5); /将调用void func(double x)c.func(3.5f); /窄化转型，调用void fu

8、nc(double x)例5-1class CleverCircledouble r;CleverCircle(double x)r = x;double getL()return 2 * Math.PI * r;double getS()return Math.PI * r * r;class Testpublic static void main(String aa)CleverCircle cc=new CleverCircle(2); System.out.println(cc.getL()+tt+cc.getS();cc=new CleverCircle(3.5); System.o

9、ut.println(cc.getL()+tt+cc.getS(); 例5-2class Flowerstatic int num=0;Flower()num+;System.out.println(num+朵花开了！);public static void main(String aa) new Flower(); new Flower(); new Flower(); 例5-3class Mycalstatic int sum(int n)int s=0;for(int i=0;i=n;i+)s+=i;return s;static int sum(int m,int n)int s=0;

10、for(int i=m;i=n;i+) s+=i;return s;public static void main(String aa) System.out.println(sum(100); System.out.println(sum(50,90); 例5-4class NewFlowerstatic int num = 0; NewFlower() /第一个构造方法，无参num +;System.out.println(num + 朵花开了！);NewFlower(String color) /第二个构造方法，带字符串型参数num +;System.out.println(num+朵花

11、开了.是+color+花！);public static void main(String args) new NewFlower(); /没有参数，调用第一个构造方法 new NewFlower(红);/带参数，调用第二个构造方法 new NewFlower(蓝);/带参数，调用第二个构造方法 例5-5class Rectangledouble w;double h;Rectangle(double x) /正方形，长宽相同w = h = x; Rectangle(double x, double y) /矩形w = x; h = y;double getS()return w * h;cl

12、ass Testpublic static void main(String aa) System.out.println(new Rectangle(2.3,4.5).getS(); System.out.println(new Rectangle(7.6).getS(); 例5-6class TagTag(int m)System.out.println(Tag(+m+);class CardTag t1=new Tag(1);Card()System.out.println(Card();t3=new Tag(33);Tag t2=new Tag(2);void f()System.ou

13、t.println(f();Tag t3=new Tag(3);class TestInit2public static void main(String aa)Card t=new Card();t.f();例5-7class TestInitA int x; Circle y; boolean z;public static void main( String args ) TestInit ti=new TestInit(); System.out.println( x is + ti.x ); System.out.println( y is + ti.y ); System.out.

14、println(z is + ti.z); 例5-8class TestInitCint x=3;TestInitC()x=5; public static void main( String args ) TestInitC t=new TestInitC(); System.out.println(t.x ); 例5-9class TestInitDTestInitD(int a)x=a;public static void main( String args )System.out.println( new TestInitD(5).x );int x=3;例5-10class Test

15、InitEString s1=String1;TestInitE()System.out.println(init);System.out.println(s2);static String s2,s3;statics2=String2;s3=String3;class Testpublic static void main(String aa)System.out.println(Creating new TestInitE);new TestInitE();System.out.println(Creating new TestInitE);new TestInitE();例5-11cla

16、ss TestOLint x;void func()System.out.println(no arg);String func(int i)return arg is + i;void func(String s)System.out.println(s);public static void main(String a)TestOL c = new TestOL();c.func();c.func(c.func(100);例5-12class TestOL1void func(double x)System.out.println(x+ is double);void func(int x

17、)System.out.println(x+ is int);public static void main(String a)TestOL1 c=new TestOL1();c.func(1); /将调用void func(int x)c.func(2.5); /将调用void func(double x)c.func(3.5f); /窄化转型，调用void func(double x)例5-13class ThisTestint a;ThisTest(int a) /参数与成员变量同名this.a = a; /成员变量a取得参数值a +;public static void main(St

18、ring args) System.out.println(new ThisTest(5).a); /结果是？ 例5-14 class TestBint a;int b;TestB(int a,int b)this.a=a;this.b=b;System.out.println(a+-+b+t+this.sum();TestB(int a)this(1,a);int sum()int s=0;for(int i=a;i=b;i+)s+=i;return s;public static void main(String aa)new TestB(10,20);new TestB(100);例5-

19、15class Triangledouble a,b,c; /三个边Triangle()a=3;b=4;c=5;Triangle(double x)a=b=c=x;Triangle(double a,double b,double c)this.a=a;this.b=b;this.c=c;double getS()if(a+b=c|c+b=a|a+c=b) return 0;double l=(a+b+c)/2;double s=Math.sqrt(l*(l-a)*(l-b)*(l-c);return s;/下面Tri类是对Triangle类的测试class Tripublic static

20、void main(String aa)System.out.println(new Triangle().getS();System.out.println(new Triangle(5).getS();System.out.println(new Triangle(5,8,6).getS();System.out.println(new Triangle(2,9,6).getS();例6-1package mylib.simple;public class Base1int x; /无权限修饰符成员变量void print() /无权限修饰符成员方法System.out.println(x

21、); /本类访问x，可行！例6-2package mylib.simple;public class Base2public int x; /public成员变量public void print() /public成员方法System.out.println(x); /本类访问pubic成员，可行！例6-3package mylib.simple;public class List public List() System.out.println(mylib.simple.List); 例6-4package my.tools;public class Ppublic static void

22、 rint(Object s)System.out.print(s);public static void rintln(Object s)System.out.println(s);例6-5class Flowerprivate Flower()System.out.println(开花了！);static Flower getFlower()return new Flower();void print()System.out.println(这是一朵美丽的花。);class PrivateFlowerTestpublic static void main(String args)Flowe

23、r f=Flower.getFlower(); /Flower f=new Flower();?f.print();例6-6package mylib.simple;class TestBase1public static void main(String args) Base1 b=new Base1();b.x=5; /同软件包中的类访问，可行！b.print(); /同上。 例6-7class TestBase2 /TestBase2类与Base2类不同软件包public static void main(String args) mylib.simple.Base2 b=new myl

24、ib.simple.Base2();b.x=5; /不同软件包中的类访问public成员，可行！b.print(); /同上。 例6-8import mylib.simple.List;class TestListpublic static void main(String args)new List(); /若无import语句，此处应为new mylib.simple.List();例6-9import my.tools.P;class TestPpublic static void main(String aa) P.rint(Its a try.); P.rintln(.); P.ri

25、nt(Math.PI); P.rintln(); P.rintln(1+2); 例6-10class Baseprivate int x=1; /private成员变量private void print() /private成员方法System.out.println(x);void doprint()print();class Testpublic static void main(String args)Base b = new Base();b.doprint(); /用b.print();替换试试！例7-1class Animalint age;double w;Animal()Sy

26、stem.out.println(Here is a animal);void eat()System.out.println(Animal.eat);void sleep()System.out.println(Animal.sleep);void breathe()System.out.println(Animal.breathe);class Fish extends AnimalFish()System.out.println(Here is a fish);void breathe()System.out.println(Fish.breathe 。);public static v

27、oid main(String aa) Fish f=new Fish(); f.eat(); f.sleep(); f.breathe(); 例7-2class ArtArt()System.out.println(Art constructor);class Drawing extends ArtDrawing()System.out.println(Drawing constructor);class Cartoon extends DrawingCartoon()System.out.println(Cartoon constructor);public static void mai

28、n(String aa)new Cartoon();例7-3class Personint salary;void employed()if (salary=0) System.out.println(no job);else System.out.println(job);class Children extends Personint age;void printAge()System.out.println(Age:+age);public static void main(String aa)Children c=new Children();c.salary=560;/从Person

29、类继承的属性变量c.age=12;/本类的属性变量c.printAge();/本类的方法c.employed();/从Person类继承的方法例7-4class A public double circleArea(double r)return Math.PI * r * r; class Bdouble r1,r2,r3;B(double a,double b,double c)r1 = a;r2 = b; r3 = c;class Test public static void main(String args)B b = new B(2, 3.5, 2.5);A a = new A()

30、;System.out.println(a.circleArea(b.r1);System.out.println(a.circleArea(b.r2);System.out.println(a.circleArea(b.r3);例7-5class A public double circleArea(double r)return Math.PI*r*r; class Bdouble r1,r2,r3;A a = new A();B(double a,double b,double c)r1 = a; r2 = b; r3 = c;class Test public static void

31、main(String args)B b = new B(2, 3.5, 2.5);System.out.println(b.a.circleArea(b.r1);System.out.println(b.a.circleArea(b.r2);System.out.println(b.a.circleArea(b.r3);例7-6class AA(int m) System.out.println(A(+m+); class B extends AB(int m)super(); /隐含System.out.println(B(+m+);public static void main(Stri

32、ng aa) new B(100); 例7-7class FinalClassprivate FinalClass()System.out.println(Its a final class);class FinalTest extends FinalClassFinalTest()System.out.println(Final Test.);public static void main(String aa)new FinalTest();例7-8class FinalMethodfinal void A() System.out.println(FinalMethod.A(); clas

33、s FinalTest1 extends FinalMethodvoid A()System.out.println(FianlTest1.A();public static void main(String aa)new FianlTest1().A();例7-9class Children extends Personint age;void printAge()System.out.println(Age:+age);void employed()System.out.println(A child should study in the school.);public static v

34、oid main(String aa)Children c=new Children();c.salary=560;/从Person类继承的属性变量c.employed();/从Person类继承的方法例7-10class A public double circleArea(double r)return Math.PI*r*r; class Bdouble r1,r2,r3;A a = new A();B(double a,double b,double c)r1 = a; r2 = b; r3 = c;class Test public static void main(String a

35、a)B b=new B(2,3.5,2.5);System.out.println(b.a.circleArea(b.r1);System.out.println(b.a.circleArea(b.r2);System.out.println(b.a.circleArea(b.r3);/class A /public double circleArea(double r)/return Math.PI*r*r;/ /class B/A a = new A(); /void printCArea(double r)/System.out.println(a.circleArea(r);/clas

36、s Test /public static void main(String a)/B b=new B();/b.printCArea(3.5);/ /class A /public double employed(double salary)/return salary*0.8;/class B /A a;/double x;/B(double x)/this.x = x;/a = new A();/class Test/public static void main(String aa)/B b=new B(1000);/System.out.println(He should get +

37、 b.x);/System.out.println(But he only get + b.a.employed(b.x);/例7-11class GrandParentGrandParent(String s)System.out.println(GrandParent +s);class Parent extends GrandParentParent(String s) super(Parent +s); /主动调用父类构造方法class Children extends ParentChildren(String s) super(Children +s); /主动调用父类构造方法pu

38、blic static void main(String a)new Children(lili);例7-12class Aint id; A(int a)id = a; void f()System.out.println(SuperClass);class B extends A int id; /对父类的成员变量进行隐蔽B(int a) super(a); void f() System.out.println(SubClass); void test() System.out.println(id+t + super.id); f(); /访问本类中重写的f方法 super.f();

39、/访问父类中被重写的f方法 public static void main(String args) (new B(5).test(); /创建B类对象并调用test方法 例7-13import javax.swing.*;class Ext extends JFrameExt()setVisible(true);setSize(300,200);public static void main(String aa)new Ext();例8-1abstract class Shape /定义抽象类Shapeabstract double getL();/求周长的方法，抽象！abstract do

40、uble getS();/求面积的方法，抽象！void printSL()/输出结果System.out.println(周长：+getL()+t面积：+getS();class Circle extends Shape/定义圆类Circledouble r;Circle(double x)r = x;double getL()return 2 * Math.PI * r; /重写抽象方法double getS()return Math.PI*r*r;class Triange extends Shape/定义三角形类Triangledouble a,b,c;Triange(double x,

41、double y,double z)a = x;b = y;c = z;double getL()return a + b + c; /重写抽象方法double getS()double l=(a+ b+ c)/2;return Math.sqrt(l-a)*(l-b)*(l-c)*l);class Square extends Shape/定义长方形类Squaredouble a,b;Square(double x,double y)a=x;b=y;double getL()return 2*(a+b); /重写抽象方法double getS()return a*b;class Testpublic