java复习题带答案(3)

2．public class PrintTest{

public static void main(String args[]){ int a=4,b=6,c=8; String s=\

System.out.println(a+b+s+c); System.out.println(); } }

3．public class SwitchTest{

public static void main(String args[]){ int i=1; switch (i) {

case 0: System.out.print(\case 1: System.out.print(\case 2: System.out.print(\

default： System.out.println(\

} } }

4. public class MultiplyList {

public static void main(String[] args) { String output=\

blabel: for(int row=1;row<=9;row++){ for(int col=row;col<=9;col++){ if(row<8)continue blabel;

output+=col+\

}

output+=\ }

System.out.println(output); System.exit(0); } }

11

5. public class Koo{

public static void main(String args[]) { int i=0,sum=0;

int[] anArray=new int[5]; while(i

anArray[i]=5-i;

System.out.print(anArray[i]+“ ”); i++; }

System.out.println(); } }

6. public class CatchTest{

public static void main(String args[]){ int[] x={0,1,2,3}; for(int i=0;i<3;i+=2){ try{

System.out.println(x[i+2]/x[i]+x[i+1]); }catch(ArithmeticException e){

System.out.println(“error1”); }catch(Exception e){

System.out.println(“error2”); } } } }

7． class GrandFather{

GrandFather(){System.out.println(“GrandFather”);}

}

class Book{

Book(){System.out.println(“Book”);} }

class Father extends GrandFather{

Father(){System.out.println(“Father”);}

}

public class Son extends Father { private Book b=new Book();

public Son(){System.out.println(“GrandFather”);} public static void main(String args[]){

12

new Son();

}

8． class Count{

public static int counter = 0 ; public Count( ){ counter++ ; }

public int getCount(){ return counter; }

}

public class StaticTest{

public static void main(String[] args){ Count[] c = new Count[5]; for(int i=0;i

System.out.println(c[i].getCount()); } } }

9． public class Calculation {

public float avg(int... nums) { int sum = 0;

for ( int x : nums ) { sum += x; }

return ((float) sum) / nums.length; }

public static void main(String args[]){ Calculation cal = new Calculation(); float av1 = cal.avg(10, 20, 30); System.out.println(av1); } }

13

10. package test;

public class OuterClass{ private class InterClass{ public InterClass(){

System.out.println(“InterClass”); } }

public OuterClass(){

InterClass ic= new InterClass(); System.out.println(“OuterClass”); }

public static void main(String args[]){ OuterClass oc=new OuterClass(); } }

11. import java.io.*;

public class FileTest{

public static void main(String args[]){ File f=new File(\ File d=new File(\ d.mkdir();

f.renameTo(new File(\ String l[]=d.list();

for(int i=0;i

12. interface ShowMessage { void 显示商标(String s); } class TV implements ShowMessage{

public void 显示商标(String s) { System.out.println(s); } }

class PC implements ShowMessage{

public void 显示商标(String s) { System.out.println(s); } }

public class Example4_28{

public static void main(String args[]){

ShowMessage sm; sm = new TV();

14

sm.显示商标(\长城牌电视机\

sm = new PC(); sm.显示商标(\联想奔月5008PC机\} }

五、程序填空

1． 以下为一个applet的完整程序，它使用”宋体”字体，在applet窗口中显示背景色为黑色，前景色为绿色的字符串”您好！”。 import java.awt.*; import Java.applet.*;

public class DrawStringDemo extends Applet{ private Font afont= Font(“宋体”,Font.BOLD,18); public void init(){

this.setBackground (Color.black); }

public void paint(Graphics g){ g.setColor(Color.green);

this.setFont (afont);

g.drawString (“您好！”,10,40); } }

2． 以下为一个java的完整程序，它定义了一个类Car，并在程序中创建了一个该类的对象DemoCar，调用该对象的set_number方法设置车号属性为3388，调用该对象的show_number方法输出车号。 //Car.java class Car{

int car_number;

void set_number(int car_num) {

car_number= car_number =car_num; ; }

void show_number(){

System.out. System.out.println (“My car No.

is :”+car_number);

} }

//CarDemo.java class CarDemo{

public static void main(String args[]){

Car Democar= Car Democar=new Car();

DemoCar.set_number( Democar.set_number(3388); ); DemoCar.show_number ();

} }

15