问题：猜字游戏

import java.util.Scanner;
public class T{
   public static void main(String[] args){
               //create a Scanner
            Scanner input = new Scanner(System.in);           
            String[] word = {"write","happy","right"};
            int i = (int)(Math.random() * 3);
            int len = word[i].length();
            
            int temp = 0,count = 0,index = 0;
            //把字符串转换成char类型的
            char[] a = word[i].toCharArray();
            while(temp < len) {
                System.out.print("Enter a letter in word *****:");
                String ch1 = input.next();
                char ch2 = ch1.charAt(0);               
                for(int k = 0;k < len;k++) {                  
                   if(ch2 == a[k]) {
                      index = k;
                      switch(index) {
                          case 0:System.out.println("Enter a letter in word " + a[0] + "****");break;
                          case 1:System.out.println("Enter a letter in word " + "*" + a[1] +"***");break;
                          case 2:System.out.println("Enter a letter in word " + "**" + a[2] + "**");break;
                          case 3:System.out.println("Enter a letter in word " + "***" + a[3] + "*");break;
                          case 4:System.out.println("Enter a letter in word " + "****" + a[4]);break;
                     }
                     temp++;
                  }                                                                                 
                }                                
                 
                    count++;  
        }                     
        System.out.print("要猜测的单词为:" + word[i] + " , " + " 你错了" + count + "次");
        input.close();
   }
}
我的计算猜错次数怎么弄都不对头
求解救