3137102408_王志强_第二次作业

第二题：

package cn.wang.mju;

import javax.swing.text.View;

public class Main {

/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
View v = new View();
}
}
package cn.wang.mju;
//import java.util.*;

public class Action {
public void findWord(String str){//划分单词
String[] arrayWord =str.split(" ");
Action a = new Action();
a.frequency(arrayWord);
}
public void frequency(String[] arrayWord){
String[] word = new String[arrayWord.length];//存放遍历过的单词
int time[]=new int[arrayWord.length];//存放记录单词出现次数
boolean t = true;
for(int i=0;i<arrayWord.length;i++){
for(int j=0;j<arrayWord.length;j++){//遍历已遍历过的单词表
if(arrayWord[i].equals(word[j])){
System.out.println("单词重复！！！");
t=false;//如果单词重复则跳过
}
}
if(t==true){//单词初始次数为1
word[i]=arrayWord[i];
time[i]=1;
for(int j=i+1;j<arrayWord.length;j++){//遍历字符串，记录次数
if(arrayWord[i].equals(arrayWord[j])){
time[i]++;
}
}
}
}
for(int i = 0;i<arrayWord.length;i++){//遍历输出次数
if(word[i]!=null){
System.out.println("单词："+word[i]+"出现了"+time[i]+"次。");
}
}
}
//以下是迭代器
/*public void frequency(String[] arrayWord){
Map<String,Integer> word = new HashMap<String,Integer>();
boolean t = true;
for(int i=0;i<arrayWord.length;i++){
Iterator<String> it = word.keySet().iterator();
while(it.hasNext()){
String key =(String)it.next();
if(key.equals(arrayWord[i])){
t=false;
}
else{
t=true;
}
}
if(t==true){
word.put(arrayWord[i],1);
int x=1;
for(int j=i+1;j<arrayWord.length;j++){
if(arrayWord[i].equals(arrayWord[j])){
x=x+1;
word.remove(arrayWord[i]);
word.put(arrayWord[i], x);
}
}
}
}
Iterator<String> i = word.keySet().iterator();
while(i.hasNext()){
String key =(String)i.next();
System.out.println("单词："+key+"出现了"+word.get(key)+"次。");
}

}*/
}
package cn.wang.mju;
import java.util.Scanner;

public class View {
public View(){
Scanner input =new Scanner(System.in);
System.out.println("请输入字符串，单词用空格隔开，回车结束：");
String str=input.nextLine();
Action a = new Action();
a.findWord(str);
}
}

第三题：
import java.util.HashMap;
import java.util.Map;
public class test2_2 {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
String a = "how are you";
String[] b = a.split(" ");
String c = "";
for(int d=b.length;d>0;d--)
{
c=c+b[d-1]+" ";
}
System.out.println(c);
}
}