Java习题集3 - 图文

for(int i=0；i

}

答：运行结果为：1 2 3 4 5 0 2 6 12 20

11、public static void main(String args[]) {

char a[][]=new char[3][3]; for(int i=0;i

for(int j=0;j=j)

a[i][j]=’*’; else

a[i][j]=’’;

for(int i=0;i

for(int j=0;j

}

答：运行结果为：* * * * * *

12、public static void main(String arg[]) {

int array[]=new int[10]； for(int i=0;i<10;i++) array[i]=i+1;

System.out.println(sum(array,array.length))； }

static int sum(int a[],int n) {

if (n>1)

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return a[n-1]+sum(a,n-1)； else

return a[0]；

}

答：运行结果为：55

13、public class CreateString

{

public static void main(String args[]) {

char cArray[]={‘一’,’路’,’顺’,’风’,’！’}; String sArray[]=new String[7];

StringBuffer sb=new StringBuffer(?很高兴见到您！?); String s=?别来无恙？?; sArray[0]=new String(s); sArray[1]=new String();

sArray[2]=new String(?节日快乐！?); sArray[3]=new String(cArray);

sArray[4]=new String(cArray,2,3); sArray[5]=new String(sb);

for(int i=0;i

答：运行结果为：别来无恙？ 节日快乐！ 一路顺风！ 顺风！

很高兴见到您！ Null 14、class Student

{

int number; String name;

Student(int number,String name) {

this.number=number;

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this.name=name;

System.out.println(\ } }

class Univer_Student extends Student {

boolean 婚否;

Univer_Student(int number,String name,boolean b) {

super(number,name); 婚否=b;

System.out.println(\婚否=\婚否); } }

public class Class1 {

public static void main (String[] args) throws java.io.IOException {

int i;

Univer_Student zhang=new Univer_Student(5144,\李晓红\ i=System.in.read(); } }

答：运行结果为：I am 李晓红 my number is 5144 婚否=false

15、class Sum

{

int n; float f() {

float sum=0;

for(int i=1;i<=n;i++) sum=sum+i; return sum; }

}

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class Average extends Sum {

int n; float f() {

float c; super.n=n; c=super.f(); return c/n; }

float g() {

float c;

c=super.f(); return c/2;

} }

public class Class1 {

public static void main (String[] args) throws java.io.IOException {

Average aver=new Average(); aver.n=100;

float result_1=aver.f(); float result_2=aver.g();

System.out.println(\ System.out.println(\ int i;

i=System.in.read();

} }

答：运行结果为：result_1=50.50 result_2=2525.0

16、

class Student {

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