Java中的生日猜測遊戲，代碼行被無緣無故地跳過

Question

我正在從Y. Daniel Liang着的「Java編程入門」一書中進行練習。在這個程序中，用戶在一個月內被呈現爲具有各種日期的表格。如果用戶的生日在所呈現的表格中，則用戶提示'是'而不是'N'。根據用戶提示'Y'的次數，程序應該猜測用戶的生日是哪一天。當我運行程序時，顯示第一組日期，我輸入'Y'或'N'。然後打印set2和3，但我不會輸入任何輸入。當打印設置4時，我可以再次鍵入輸入，但是在打印設置5之後，不能輸入任何輸入。爲什麼我只能在set1和4之後輸入輸入內容？代碼顯示如下：

import java.util.Scanner; 


public class GuessBirthday { 

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

String set1 = 
    " 1 3 5 7\n" + 
    " 9 11 13 15\n" + 
    " 17 19 21 23\n" + 
    " 25 27 29 31"; 

    String set2 = 
    " 2 3 6 7\n" + 
    " 10 11 14 15\n" + 
    " 18 19 22 23\n" + 
    " 26 27 30 31"; 

    String set3 = 
    " 4 5 6 7\n" + 
    " 12 13 14 15\n" + 
    " 20 21 22 23\n" + 
    " 28 29 30 31"; 

    String set4 = 
    " 8 9 10 11\n" + 
    " 12 13 14 15\n" + 
    " 24 25 26 27\n" + 
    " 28 29 30 31"; 

    String set5 = 
    " 16 17 18 19\n" + 
    " 20 21 22 23\n" + 
    " 24 25 26 27\n" + 
    " 28 29 30 31"; 

    int day = 0; 

    // Create a scanner 

    Scanner input = new Scanner(System.in); 

    // Prompt the user to answer questions 

    System.out.print("Is your birthday in set1?\n"); 
    System.out.print(set1); 
    System.out.print("\nEnter (Y) for yes or (N) for no: "); 
    char answer = (char) System.in.read(); 

    if (answer == 'Y') 
     day += 1; 

    System.out.print("\nIs your birthday in set2?\n"); 
    System.out.print(set2); 
    System.out.print("\nEnter (Y) for yes or (N) for no: "); 
    answer = (char) System.in.read(); 

    if (answer == 'Y') 
     day += 2; 

    System.out.print("\nIs your birthday in set3?\n"); 
    System.out.print(set3); 
    System.out.print("\nEnter (Y) for yes or (N) for no: "); 
    answer = (char) System.in.read(); 

    if (answer == 'Y') 
     day += 4; 

    System.out.print("\nIs your birthday in set4?\n"); 
    System.out.print(set4); 
    System.out.print("\nEnter (Y) for yes or (N) for no: "); 
    answer = (char) System.in.read(); 

    if (answer == 'Y') 
     day += 8; 

    System.out.print("\nIs your birthday in set5?\n"); 
    System.out.print(set5); 
    System.out.print("\nEnter (Y) for yes or (N) for no: "); 
    answer = (char) System.in.read(); 

    if (answer == 'Y') 
     day += 16; 

    System.out.println("\nYour birthday is " + day + "!"); 

    } 
} 

Answer 1

，你只能讀1和焦炭在時間，因爲你正在使用System.in.read()吞噬換行符。回車符（\ r）和/或換行符（\ n）將被視爲字符。因此，在第一次輸入時，例如在輸入'Y \ r \ n'的窗口中，所以System.in.read（）第一次會得到'Y'，下次會收到'\ r'。

您可以使用Scanner你實例化..

String answer = input.nextLine(); 
if (answer.equals("Y") { 
    // blah 
} 

Answer 2

你永遠實際上您的來電System.in.read（）

Answer 3

我想知道同樣的事情（用0和1的是奇怪），所以在這裏誰絆倒任何人，我得到它的工作（注意：你也可以用'char'來代替'char'這個單詞）：

import java.util.Scanner; 


public class GuessBirthday 
{ 
public static void main(String [] args) 
{ 

String set1 = 
" 1 3 5 7\n" + 
" 9 11 13 15\n" + 
" 17 19 21 23\n" + 
" 25 27 29 31"; 

String set2 = 
" 2 3 6 7\n" + 
" 10 11 14 15\n" + 
" 18 19 22 23\n" + 
" 26 27 30 31"; 

String set3 = 
" 4 5 6 7\n" + 
" 12 13 14 15\n" + 
" 20 21 22 23\n" + 
" 28 29 30 31"; 

String set4 = 
" 8 9 10 11\n" + 
" 12 13 14 15\n" + 
" 24 25 26 27\n" + 
" 28 29 30 31"; 

String set5 = 
" 16 17 18 19\n" + 
" 20 21 22 23\n" + 
" 24 25 26 27\n" + 
" 28 29 30 31"; 

int day = 0; 

// Create a scanner 

Scanner input = new Scanner(System.in); 

// Prompt the user to answer questions 

System.out.print("Is your birthday in set1?\n"); 
System.out.print(set1); 
System.out.print("\nEnter (Y) for yes or (N) for no: "); 
String answer = input.next(); 

if (answer.equals("Y")) 
    day += 1; 

System.out.print("\nIs your birthday in set2?\n"); 
System.out.print(set2); 
System.out.print("\nEnter (Y) for yes or (N) for no: "); 
answer = input.next(); 

if (answer.equals("Y")) 
    day += 2; 

System.out.print("\nIs your birthday in set3?\n"); 
System.out.print(set3); 
System.out.print("\nEnter (Y) for yes or (N) for no: "); 
answer = input.next(); 

if (answer.equals("Y")) 
    day += 4; 

System.out.print("\nIs your birthday in set4?\n"); 
System.out.print(set4); 
System.out.print("\nEnter (Y) for yes or (N) for no: "); 
answer = input.next(); 

if (answer.equals("Y")) 
    day += 8; 

System.out.print("\nIs your birthday in set5?\n"); 
System.out.print(set5); 
System.out.print("\nEnter (Y) for yes or (N) for no: "); 
answer = input.next(); 

if (answer.equals("Y")) 
    day += 16; 

System.out.println("\nYour birthday is " + day + "!"); 

} 
}