计算机网络专业自考Java实践考核答案.doc

Java语言Under MC-DOS1)Path=C:Javajdk1.6.0_05bin2)set Classpath=C:Javajdk1.6.0_05jrelibrt.jar;.;第一题class People protected String name;protected int age;public int getAge() return age; class Employee extends People protected String empno; class Teacher extends People String teano; String zc; 第二题Application:public class HelloWorld public static void main (String args) System.out.println(Hello World!); Applet:源程序：import java.applet.*;import java.awt.*;public class HelloWorldApplet extends Applet public void paint(Graphics g) g.drawString(Hello World!,10,20); 运行(编写html文件)：HelloWorldApplet 第三题源程序：Running OK.import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.lang.Double;public class ExampleThree public static void main (String args) ComputerFrame fr=new ComputerFrame(); fr.setTitle(求绝对值); class ComputerFrame extends JFrame implements ActionListener JTextField text1,text2; JButton button; public ComputerFrame() setLayout(new FlowLayout(); text1=new JTextField(10); text2=new JTextField(10); add(text1); button=new JButton(绝对值); add(button); add(text2); button.addActionListener(this); setSize(400,320); setVisible(true); validate(); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); public void actionPerformed(ActionEvent e) Double n; if(e.getSource()=button) Double m; try m=Double.parseDouble(text1.getText(); n=Math.abs(m); text2.setText(String.valueOf(n); catch(NumberFormatException ee) text2.setText(请输入数字字符); validate(); 运行(编写html文件)：Running error.ExampleThree 第四题 import java.lang.Double;public class ExampleFourpublic static void main (String args) Fractor r1; r1=new Fractor(-2,9); Fractor r2; r2=new Fractor(3,7); Fractor result1=r1.add(r2); Fractor result2=r1.sub(r2); System.out.printf(两分数之和：); r1.diplay(); System.out.printf(+); r2.diplay(); System.out.printf(=); result1.diplay(); System.out.printf(n); System.out.printf(两分数之差：); r1.diplay(); System.out.printf(-); r2.diplay(); System.out.printf(=); result2.diplay(); System.out.printf(n); class Fractor int m; /分子 int n; /分母 Fractor(int m, int n) /设置分子和分母 int c=f(Math.abs(m),Math.abs(n); /计算最大公约数 this.m=m/c; this.n=n/c; if(m0&n0) m=-m; n=-n; int getNumerator() /得到分子 return m; int getDenominator() /得到分母 return n; public int f(int k,int v) if(kv) int c=k; k=v; v=c; int r=k%v; while(r!=0) k=v; v=r; r=k%v; return v; Fractor add(Fractor a) int k=a.getNumerator(); int v=a.getDenominator(); int newM=m*v+n*k; int newN=n*v; Fractor result=new Fractor(newM,newN); return result; Fractor sub(Fractor a) int k=a.getNumerator(); int v=a.getDenominator(); int newM=m*v-n*k; int newN=n*v; Fractor result=new Fractor(newM,newN); return result; void diplay() int m=getNumerator(); int n=getDenominator(); System.out.printf(0+m+/+n+0); 第五题第六题public class ExampleSix public static void main (String args) int arrayOfInts=32,87,3,589,12,1076,2000,8,622,127; for(int i=0;iarrayOfInts.length;i+) for(int j=i+1;jarrayOfInts.length;j+) if(arrayOfIntsjarrayOfIntsi) int temp=0; temp=arrayOfIntsj; arrayOfIntsj=arrayOfIntsi; arrayOfIntsi=temp; for(int k=0;karrayOfInts.length;k+) System.out.printf(%6d,arrayOfIntsk); 第七题public class ExampleSeven public static void main (String args) double sum=0,a=1; int i=1; while (i=20) sum=sum+a; i+; a=a*i; System.out.println(sum=+sum); 第八题第九题import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.lang.Double;public class ExampleNine public static void main (String args) ComputerFrame fr=new ComputerFrame(); fr.setTitle(计算); class ComputerFrame extends JFrame implements ActionListener JTextField text1,text2; JButton button1,button2; JLabel label; public ComputerFrame() setLayout(new FlowLayout(); text1=new JTextField(10); text2=new JTextField(10); label=new JLabel( ,JLabel.CENTER); label.setBackground(Color.green); add(text1); add(text2); button1=new JButton(平均值); button2=new JButton(最大值); add(button1); add(button2); add(label); button1.addActionListener(this); button2.addActionListener(this); setSize(400,320); setVisible(true); validate(); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); public void actionPerformed(ActionEvent e) Double n; if(e.getSource()=button1) Double n1,n2; try n1=Double.parseDouble(text1.getText(); n2=Double.parseDouble(text2.getText(); n=(n1+n2)/2.0; label.setText(String.valueOf(n); catch(NumberFormatException ee) label.setText(请输入数字字符); else if(e.getSource()=button2) Double n1,n2; try n1=Double.parseDouble(text1.getText(); n2=Double.parseDouble(text2.getText(); n=Math.max(n1,n2); label.setText(String.valueOf(n); catch(NumberFormatException ee) label.setText(请输入数字字符); validate(); 第十题 class Point float x,y; Point() x=0.0f; y=0.0f; Point(float x,float y) this.x=x; this.y=y; float getX() return x; float getY() return y; public void show() System.out.println(点的坐标:+(+getX()+,+getY()+); public class ExampleTen public static void main (String args) Point point1=new Point(10.3f,-20.6f); Point point2=new Point(); point1.show(); point2.show(); 第十一题 abstract class Shape abstract double GetArea(); abstract double GetPerimeter();class Rectangle extends Shape double a,b; /长，宽; Rectangle(double a,double b) this.a=a; this.b=b; double GetArea() return a*b; double GetPerimeter() return (a+b)*2; class Circle extends Shape double r; Circle(double r) this.r=r; double GetArea() return 3.14*r*r; double GetPerimeter() return 3.14*r*2; public class ExampleEleven public static void ma