package Practice;

public class tt {
    public static void main(String[] args) {
        String str = "banana";
        System.out.println(str.indexOf('z')); // -1
        System.out.println(str.indexOf('a', 2)); // 3

        StringBuilder words = new StringBuilder();
        for (int i = 0; i < 5; i++)
            words.append('*'); // "*****"
        System.out.println(words.length()); // 5
        System.out.println(words.indexOf("a"));// -1
        System.out.println(words.indexOf("*", 1)); // 1
        words.setCharAt(3, 'a'); // "***a*"
        System.out.println(words);
    }
}

package Practice;

import java.util.Scanner;

public class Guess {
    public static String words[] = {"banana", "telecommunication", "programming", "bupt"};
    public static boolean[] guessed = new boolean[words.length]; // 判断猜过
    public static int num_guessed = 0; // 猜过的单词数量
    public static char keep; // 是否继续y or n

    public static void main(String[] args) {
//        for(int i = 0; i < guessed.length; i ++ ) System.out.println(guessed[i]);
        Scanner scanner = new Scanner(System.in);

        do{
            // 随机产生要猜测的单词  ans
            int index = (int) (Math.random() * words.length);
            String ans = words[index];
            // 再来一次时的重复检测
            while(guessed[index] == true)
            {
                index = (int) (Math.random() * words.length);
                ans = words[index];
            }

            // 初始化，StringBuilder类似list
            StringBuilder guessedWord = new StringBuilder();
            for (int i = 0; i < ans.length(); i++)
                guessedWord.append('*');

            int numberOfCorrectLettersGuessed = 0, numberOfMisses = 0;

            // 模拟过程
            while (numberOfCorrectLettersGuessed < ans.length()) {
                System.out.print("(Guess) Enter a letter in word " + guessedWord
                        + " > ");
                String s = scanner.nextLine();
                char letter = s.charAt(0);

                if (guessedWord.indexOf(letter + "") >= 0) { // 猜中，但重复，不算错误次数
                    System.out.println("	" + letter + " is already in the word");
                } else if (ans.indexOf(letter) < 0) { // 猜错
                    System.out.println("	" + letter + " is not in the word");
                    numberOfMisses++;
                } else { // 猜中，进行标记与赋值
                    int k = ans.indexOf(letter);
                    while (k >= 0) {
                        guessedWord.setCharAt(k, letter);
                        numberOfCorrectLettersGuessed++;
                        k = ans.indexOf(letter, k + 1);
                    }
                }
            }

            System.out.println("The word is " + ans + ". You missed "
                    + numberOfMisses + ((numberOfMisses <= 1) ? " time" : " times"));

            guessed[index] = true;
            num_guessed += 1;

            if(num_guessed < words.length)
            {
                System.out.print("Do you want to guess for another word? Enter y or n> ");
                keep = scanner.nextLine().charAt(0);
            }

        }while(keep == 'y' && num_guessed < words.length);

        if(keep == 'y')
            System.out.println("Perfect!!!");
        else
            System.out.println("You have guessed " + num_guessed + ((num_guessed <= 1) ? " word~" : " words~"));


    }
}