语言程序设计资料：java程序设计教程源代码

1、第一章 Java语言的概述例子1class A void f() System.out.println(I am A); class Bpublic class Hello public static void main (String args ) System.out.println(你好，很高兴学习Java); A a=new A(); a.f(); 源程序public class Tom int leg; String head; void cry(String s) System.out.println(s); class Example public static void mai

2、n(String args) Tom cat; cat=new Tom(); cat.leg=4; cat.head=猫头; System.out.println(腿:+cat.leg+条); System.out.println(头:+cat.head); cat.cry(我今天要和Jerry拼了); 例子2import java.applet.*; import java.awt.*;public class Boy extends Applet public void paint(Graphics g) g.setColor(Color.blue); g.drawString(Java是

3、一门很优秀的语言,12,30); g.setColor(Color.red); g.drawString(我一定认真学习Java,22,56); 第2章 基本数据类型和数 例子1public class Example public static void main (String args ) char c=; System.out.println(希腊字母在unicode表中的顺序位置:+(int)c); System.out.println(希腊字母表：); for(int i=(int);i=(int);i+) System.out.print( +(char)i); 例子2 publ

4、ic class Example public static void main (String args ) byte a=120; short b=255; int c=2200; long d=8000; float f; double g=0.1234567812345678; b=a; c=(int)d; f=(float)g; /导致精度的损失. System.out.println(a=+a); System.out.println(b=+b); System.out.println(c=+c); System.out.println(d=+d); System.out.prin

5、tln(f=+f); System.out.println(g=+g); 例子3 public class Example public static void main (String args ) long x=5678; float f=123.456789f; double d=123456.12345678; char c=a; System.out.printf(%cn%10.3f%n%f,%12d%n%d,c,f,d,x=x+2,x); 例子4 import java.util.*;public class Example public static void main (Str

6、ing args ) System.out.println(请输入若干个数，每输入一个数回车确认); System.out.println(最后输入一个非数字结束输入操作); Scanner reader=new Scanner(System.in); double sum=0; int m=0; while(reader.hasNextDouble() double x = reader.nextDouble(); m=m+1; sum=sum+x; System.out.printf(%d个数的和为%fn,m,sum); System.out.printf(%d个数的平均值是%fn,m,s

7、um/m); 例子5 public class Example public static void main(String args) int a=1,2,3; int b; b=a; b2=100; System.out.printf(a0=%-3da1=%-3da2=%-3dn,a0,a1,a2); System.out.printf(b0=%-3db1=%-3db2=%-3dn,b0,b1,b2); 第3章 运算符、表达式与语句 例子1import java.util.*;public class Example public static void main (String args

8、 ) Scanner reader=new Scanner(System.in); System.out.println(输入待移位的int型整数:); int x = reader.nextInt(); System.out.println(输入移位量:); int n = reader.nextInt(); System.out.println(左移位的结果:+(xn); 例子2class Example public static void main(String args) char a=金,木,水,火,土; char secret=z; for(int i=0;ia.length;i

9、+) ai=(char)(aisecret); System.out.printf(密文:n); for(int i=0;ia.length;i+) System.out.printf(%3c,ai); for(int i=0;ia.length;i+) ai=(char)(aisecret); System.out.printf(n原文:n); for(int i=0;ic&a+cb&b+ca) if(a*a=b*b+c*c|b*b=a*a+c*c|c*c=a*a+b*b) System.out.printf(n%-8.3f%-8.3f%-8.3f构成是直角三角形,a,b,c); else

10、if(a*ab*b+c*c&b*ba*a+c*c&c*ca*a+b*b) System.out.printf(n%-8.3f%-8.3f%-8.3f构成锐角三角形,a,b,c); else System.out.printf(n%-8.3f%-8.3f%-8.3f构成钝角三角形,a,b,c); else System.out.printf(%f,%f,%f不能构成三角形,a,b,c); 例子4import java.util.*;public class Example public static void main (String args ) Scanner reader=new Scan

11、ner(System.in); System.out.println(输入一个月份:); int n=reader.nextInt(); switch(n) case 1 : case 2 : case 3 : System.out.printf(%d月属于第一季度,n); break; case 4 : case 5 : case 6 : System.out.printf(%d月属于第二季度,n); break; case 7 : case 8 : case 9 : System.out.printf(%d月属于第三季度,n); break; case 10 : case 11 : cas

12、e 12 : System.out.printf(%d月属于第四季度,n); break; default: System.out.printf(%d不代表月份,n); 例子5public class Example public static void main (String args ) double sum=0,item=1; int i=1; while(i=1000) sum=sum+item; i+; item=item*(1.0/i); sum=sum+1; System.out.println(e=+sum); sum=0; i=1; item=1; do sum=sum+i

13、tem; i+; item=item*(1.0/i) ; while(i=1000); sum=sum+1; System.out.println(e=+sum); 例子6public class Example public static void main (String args ) int sum,i,j; for(i=1;i=1000;i+) for(j=1,sum=0;j=i/2;j+) if(i%j=0) sum=sum+j; if(sum=i) System.out.printf(%8d是一个完数%n,i); 例子7class Example public static voi

14、d main(String args) int sum=0,i,j; for( i=1;ib?a:b; class Example public static void main(String args) double max=Computer.max(12,45); /类名调用类方法。 System.out.println(max); 例子5class Tom void f(int x,double y) x=x+1; y=y+1; System.out.printf(参数x和y的值分别是:%d,%fn,x,y); public class Example public static voi

15、d main(String args) int x=10; double y=12.58; Tom tom=new Tom(); tom.f(x,y); System.out.printf(main方法中x和y的值仍然分别是:%d,%fn,x,y) 例子6class Tom void f(Jerry a) a.setLeg(12); System.out.println(参数a的成员leg的值:+a.getLeg(); a=null; class Jerry int leg; Jerry(int n) leg=n; void setLeg(int n) leg=n; int getLeg()

16、return leg; public class Example public static void main(String args) Tom tom=new Tom(); Jerry jerry=new Jerry(2); System.out.println(在调用方法f之前,jerry的成员leg的值:+jerry.getLeg(); tom.f(jerry); System.out.println(在调用方法f之后,jerry的成员leg的值:+jerry.getLeg(); 例子7class Circle double radius; Circle(double r) radiu

17、s=r; double computerArea() return 3.14*radius*radius; void setRadius(double newRadius) radius=newRadius; double getRadius() return radius; class Cone Circle bottom; double height; Cone(Circle c,double h) bottom=c; height=h; double computerVolume() double volume; volume=puterArea()*height/3

18、.0; return volume; void setBottomRadius(double r) bottom.setRadius(r); double getBottomRadius() return bottom.getRadius(); class Example public static void main(String args) Circle circle=new Circle(10); Cone circular=new Cone(circle,20); System.out.println(circular的bottom半径:+circular.getBottomRadiu

19、s(); System.out.println(circular的体积:+puterVolume(); circular.setBottomRadius(100); System.out.println(circular的bottom半径:+circular.getBottomRadius(); System.out.println(circular的体积:+puterVolume(); 例子8class People float getArea(float r) return 3.14f*r*r; double getArea(float x,

20、int y) return x*y; float getArea(int x,float y) return x*y; double getArea(float x,float y,float z) return (x*x+y*y+z*z)*2.0; public class Example public static void main(String args) People zhang=new People(); System.out.println(求半径是100的圆的面积:+zhang.getArea(100); System.out.println(求单位立方体的表面积:+zhang

21、.getArea(1,1,1); 例子9class Tom int leg; Tom(int n) this.cry(); leg=n; this.cry(); void cry() System.out.println(我是Tom ,我现在有+leg+条腿); public static void main(String args) Tom tom=new Tom(4); 例子10package tom.jiafei;class Tom void speak() System.out.println(Tom类在tom.jiafei包中); public class Example publi

22、c static void main(String args) Tom tom=new Tom(); tom.speak(); System.out.println(Example类在tom.jiafei包中); 例子11import java.util.Date;public class Example public static void main(String args) Date date=new Date(); System.out.println(本地机器的时间:+date); SquareEquation.java：package tom.jiafei;public class

23、SquareEquation double a,b,c; double root1,root2; boolean boo; public SquareEquation(double a,double b,double c) this.a=a; this.b=b; this.c=c; if(a!=0) boo=true; else boo=false; public void getRoots() if(boo) System.out.println(是一元2次方程); double disk=b*b-4*a*c; if(disk=0) root1=(-b+Math.sqrt(disk)/(2*

24、a); root2=(-b-Math.sqrt(disk)/(2*a); System.out.printf(方程的根:%f,%fn,root1,root2); else System.out.printf(方程没有实根n); else System.out.println(不是一元2次方程); public void setCoefficient(double a,double b,double c) this.a=a; this.b=b; this.c=c; if(a!=0) boo=true; else boo=false; 例子12import tom.jiafei.*;class E

25、xample public static void main(String args ) SquareEquation equation=new SquareEquation(4,5,1); equation.getRoots(); equation.setCoefficient(-3,4,5); equation.getRoots(); SquareEquation.java：public class SquareEquation public SquareEquation(double a,double b,double c) System.out.println(我没有包名,我和使用我的

26、程序在同一目录中 ); System.out.println(你好,我先被加载了!); public void getRoots() System.out.println(你好,我已经被加载了!); public void setCoefficient(double a,double b,double c) System.out.println(随便改吧); 例子13import tom.jiafei. SquareEquation;class Test public static void main(String args) SquareEquation equation=new Squar

27、eEquation(4,5,1); equation.getRoots(); equation.setCoefficient(-3,4,5); equation.getRoots(); 例子14class Example private int money; Example() money=2000; private int getMoney() return money; public static void main(String args) Example exa=new Example(); exa.money=3000; int m=exa.getMoney(); System.ou

28、t.println(money=+m); 例子15public class Example public static void main(String args ) char a=a,b,c,D,E,F; for(int i=0;ia.length;i+) if(Character.isLowerCase(ai) ai=Character.toUpperCase(ai); else if(Character.isUpperCase(ai) ai=Character.toLowerCase(ai); for(int i=0;ia.length;i+) System.out.printf(%6c

29、,ai); 第五章 继承、接口与泛型例子1class Father private int moneyDollar=300; int moneyHK=200; int add(int x,int y) return x+y; class Son extends Father int moneyRMB=120; public void changMoneyHK(int x) moneyHK=x; int subs(int x,int y) return x-y; class GrandSon extends Son public void changMoneyRMB(int x) moneyRM

30、B=x; int multi(int x,int y) return x*y; public class Example public static void main(String args) int a=5,b=3; Son son=new Son(); GrandSon sunzi=new GrandSon(); son.changMoneyHK(60); System.out.printf(儿子有港币,是继承的:%d,人民币,新增的的属性:%dn, son.moneyHK,son.moneyRMB); System.out.printf(儿子会减法,儿子新增的功能,%d-%d等于%dn, a,b,son.subs(a,b); System.out.printf(儿子还会加法,是继承的功能,%d+%d等于%dn, a,b,son.add(a,b); sunzi.changMoneyHK(20); sunzi.changMoneyRMB(10); System.out.printf(孙子有港币,是继承的:%d,人民币:%dn, sunzi.moneyHK,sunzi.moneyRMB); System.out.printf(孙子会乘