发布时间 : 星期一 文章Java习题集3 - 图文更新完毕开始阅读
float math,english,sum; float f(float k1,float k2) {
sum=k1*math+k2*english; return sum; } }
public class Average {
Student wanghong,lihong;
public static void main(String args[]) {
wanghong=new Student(); lihong=new Student(); wanghong.math=60.0f; wanghong.english=80f; lihong.math=70.0f; lihong.english=90.0f;
wanghong.sum=wanghong.f(2.0f,2.0f); lihong.sum=lihong.f(2.0f,2.0f);
System.out.println(\
System.out.println(\ } }
答：运行结果为：lihong sum=320.0 wanghong sum=280.0
17、
import java.awt.*; class Chengji {
float f(float x,float y) {
return x*y; } }
class Xiangjia extends Chengji {
- 29 -
//重写父类的f方法
float f(float x,float y) {
return x+y; } }
public class Class1 {
Xiangjia sum;
public static void main(String args[]) {
sum=new Xiangjia();
System.out.println(\
//此处对象sum是调用自已的方法f,得到两数的和. } }
答：运行结果为：sum=10.0
18、
public class Class1 {
float a[];
public static void main(String args[]) {
a=new float[5]; a[0]=23.9f; a[1]=34.9f; a[2]=45f; a[3]=56.98f; a[4]=100f;
System.out.println (\ System.out.println (\ System.out.println (\ System.out.println (\ System.out.println (\ } }
- 30 -
答：运行结果为： a[0]=23.9 a[1]=34.9 a[2]=45.0 a[3]=56.98 a[4]=100.0
19、
public class Class1 {
String tom=\ int x,y,z;
public static void main(String args[]) {
x=tom.indexOf(\
y=tom.indexOf(\ z=tom.indexOf(\ g.setColor(Color.red);
System.out.println(\ } }
答：运行结果为：2:7:13
20、
public class Class1 {
String jerry=\
public static void main(String args[]) {
s1=jerry.substring(2); s2=jerry.substring(2,5); g.setColor(Color.blue); System.out.println (s1); System.out.println (s2);
System.out.println (jerry.substring(jerry.indexOf(\ } }
答：运行结果为：love Tom
- 31 -
lov
love Tom
21、
import java.util.*; import java.awt.*; public class Class1 {
public static void main (String[] args) throws java.io.IOException {
String s1=\ String s2=\
StringTokenizer fenxi_1=new StringTokenizer(s1,\空格和逗号做分隔符
StringTokenizer fenxi_2=new StringTokenizer(s2,\空格和问号做分隔符
int n1=fenxi_1.countTokens(); int n2=fenxi_2.countTokens(); while(fenxi_1.hasMoreTokens()) {
String s=fenxi_1.nextToken(); System.out.print(s+? ?); }
System.out.println();
System.out.println(\有单词:\个\ while(fenxi_2.hasMoreTokens()) {
String s=fenxi_2.nextToken(); System.out.print(s+? ?); }
System.out.println();
System.out.println(\有单词:\个\ int i;
i=System.in.read(); } }
答：运行结果为：I am Geng.X.Y she is my girlfriend s1有单词：7个
- 32 -