《java程序设计》期末复习题

Inher3_1(){ //x1 a=1; }

Inher3_1(int a){ //x2 this.a=a; } }

public class Inher3 extends Inher3_1{ int b;

Inher3(int a, int b){ //x3 super(a); //x4 this.b=b; //x5 }

public static void main(String[] args){ Inher3 ob=new Inher3(10,20); //x6 System.out.println(ob.a+” “+ob.b); //x7 }}

32、class Inher6_1{ void hello(){

System.out.println(“Hi～～”); } }

public class Inher6 extends Inher6_1{ void hello(){ //覆盖

super.hello(); //调用继承而来的hello()方法 System.out.println(“高兴”); //功能的扩展 }

public static void main(String[] args){ Inher6 ob=new Inher6(); ob.hello(); }}

33、 class Super{ int a=10; void hi(){

System.out.println(\你好~~\ } }

class Sub extends Super{ int b=20; void hi(){

System.out.println(\ }

void bye(){

System.out.println(\ }}

public class Inher9{

public static void main(String[] args){ Super ob=new Sub(); ob.a=20; ob.hi();

//ob.b=30;错误 //ob.bye();错误 }}

34、public class Excep2{

public static void main(String[] args){ System.out.println(\开始程序\ int a=1,b=0; try{

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int c=a/b; //x1 System.out.println(c); //x2 }catch(ArithmeticException ae){ //x3

System.out.println(\不能被0除！\ }

System.out.println(\退出程序\ }}

35、 public class Excep7{

static void go() throws NegativeArraySizeException{ int[] a=new int[-1]; //x1 }

static void hi() throws NegativeArraySizeException{ go(); //x2 }

public static void main(String[] args){ try{ hi();

}catch(NegativeArraySizeException e){

System.out.println(\捕获来自远方的异常.\ } } }

36、import java.io.IOException; public class Excep10{

public static void main(String[] args){ int a=0;

System.out.print(\请敲入字符>> \ try{

a=System.in.read(); }catch(IOException e){

System.out.println(\错误~~~~\ }

System.out.println(\敲入的字符为： \ }}

37、阅读程序，回答问题 1、

1: public class Output1 {

2: public static void main(String arge[]) { 3: int i=0;

4: for ( char ch = 97; ch<113; ch++,i++) { 5: if( i % 8 == 0 )

6: System.out.println(\7: System.out.print(\8: } 9: } 10: }

(1) 程序第 5 、 6 行的 if 语句的功能是什么？ (2) 程序输出的结果有几行？

【 答案 】 (1) 每打印 8 个字符，则换行。 (2) 输出的结果有 2 行。 38、写出下面程序的运行结果。 1、import java.io.*; public class abc

{ public static void main(String args[ ]) { AB s = new AB(\ System.out.println(s.toString( )); } }

class AB { String s1; String s2;

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AB( String str1 , String str2 ) { s1 = str1; s2 = str2; } public String toString( ) { return s1+s2;} }

答：Hello! I love JAVA. 2、import java.io.* ; public class abc {

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

int a[ ] = { 10 , 20 , 30 , 40 , 50 , 60 , 70 , 80 , 90 }; for ( i = 0 ; i < a.length ; i ++ ) if ( a[i]%3 = = 0 ) s += a[i] ; System.out.println(\ } }

答：s = 180

3、 import java.io.* ; public class abc {

public static void main(String args[ ])

{ SubSubClass x = new SubSubClass(10 , 20 , 30); x.show(); } }

class SuperClass { int a,b;

SuperClass(int aa , int bb) { a=aa; b=bb; } void show( )

{ System.out.println(\ }

class SubClass extends SuperClass { int c;

SubClass(int aa,int bb,int cc) { super(aa,bb); c=cc; } }

class SubSubClass extends SubClass { int a;

SubSubClass(int aa,int bb,int cc) { super(aa,bb,cc); a=aa+bb+cc; }

void show()

{ System.out.println(\ }

答：a=60 b=20 c=30

4、 import java.io.*; public class abc {

public static void main(String args[]) {

String s1 = \

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String s2 = new String(\ System.out.println(s1.concat(s2)); } }

答：Hello! World! 5、 import java.io.* ; public class ABC {

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

int a[ ] = { 11,22,33,44,55,66,77,88,99 }; for ( i = 0 ; i <= a.length / 2 ; i ++ )

System.out.print( a[i]+a[a.length-i-1]+\ System.out.println( ); } }

答：110 110 110 110 110 6、 import java.io.*; class Parent {

void printMe() {

System.out.println(\ }}

class Child extends Parent {

void printMe() {

System.out.println(\ }

void printAll() {

super.printMe(); this.printMe(); printMe(); }}

public class Class1 {

public static void main(String args[ ]) {

Child myC = new Child( ); myC.printAll( ); }}

答：parent child child

39、编写一个字符界面的Java Application 程序，接受用户从键盘输入的一个正整数，然后统计并输出从1到这个正整数的累加和。

答：参考程序如下： import java.io.*; public class SUM {

public static void main (String[] args) {

int i , n=-1 , sum=0 ; do{ try {

BufferedReader br =

new BufferedReader( new InputStreamReader(System.in)); n = Integer.parseInt(br.readLine( ));

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