如何打破else語句並退出程序

Question

package oddsorevens;``      
import java.util.Scanner; 
import java.util.Random; 

public class OddsOrEvens 
{ 

public static void main(String[] args) 
{ 

    Scanner name= new Scanner (System.in); // getting input from user 
    System.out.print("Hi! What's your name: "); 
    String user = name.nextLine(); // getting user name 
    System.out.println("Hello: "+user); 
    System.out.println("Let's play OddsOrEvens"); 
    System.out.println("Choose Odd or Even"); 
    String s ="oddOrEven"; 
    Scanner str = new Scanner(System.in); // getting new string from user 
    String s1 = str.next(); //storing odd or even here 
    o: 
    if (s1.equals("even")||(s1.startsWith("e"))) 
    { 
     System.out.println("You choose even"); 
     System.out.println("Computer choose odd"); 
    } 
    else if (s1.equals("odd")||(s1.startsWith("o"))) 
    { 
     System.out.println("You choose odd"); 
     System.out.println("Computer choose even"); 
    } 
    else 
    { 
      System.out.println("Entered wrong keyword"); 
    }  
    System.out.print("How many fingers you want to put out: "); 
    Scanner num = new Scanner(System.in); 
    int n=num.nextInt(); 
    Random rand = new Random(); 
    int computer = rand.nextInt(6); 
    System.out.println("Computer choose "+ computer +" fingers"); 
    int sum; 
    sum=n+computer; 
    System.out.println(sum); 
    if(sum%2==0) 
    { 
     System.out.println(sum+" is even"); 
    } 
    else 
    { 
     System.out.println(sum+" is odd"); 
    } 
     int u = s1.length(); 
      if(u/2==0) 
      { 
       System.out.println("You won :)"); 
      } 
      else 
      {`` 
       System.out.println("You lose :(");  
      }  
} 



} 

這是我在java中的第一個pgm。在這裏如果用戶輸入錯誤的關鍵字pgm應該是中斷的並且根據用戶輸入輸出的pgm將會輸贏。請幫助。

Answer 1

無論何時您希望應用程序停止，您都必須明確告訴您要退出。要做到這一點你剛纔寫的代碼行，這是System.exit(0)

下面的示例代碼，以便更好地理解它：

public static void main(String[] args) { 
    Scanner s = new Scanner(System.in); 
    if (s.next().equals("o")) { 
    System.out.println("game is still on"); 
    } else { 
    System.out.println("game end!"); 
    System.exit(0); 
    } 
}