如果驗證不正確，如何使用Java中的J.option註冊結束程序

Question

ane.showMessageDialog（null，「錯誤：性別必須爲F或M」）;
}

} else { 
    //Write an error for invalid Age 
    JOptionPane.showMessageDialog(null,"Erlll") ; 

    } 






}//end main 

}//end class 

Answer 1

只是移動，要求對性別的if分支對應於可接受的年齡裏面的代碼：

public static void main (String[] args) { 

    final int DRINKING_AGE = 21; 
    final int ADULT = 18; 
    final String LEGAL_DRINKING_AGE_MESSAGE = "You are legally able to drink"; 

    int age = Integer.parseInt(JOptionPane.showInputDialog("Enter Your Age")); 

    boolean ageCheck = age >0 && age <=100; 
    //check to see if the age is within range 
    if (ageCheck) { 
    String gender = JOptionPane.showInputDialog("Enter Your Gender (F/M)"); 
    boolean genderCheck = gender.equalsIgnoreCase("M") || gender.equalsIgnoreCase("F"); 
    //check to see if the user entered M or F 
    if (genderCheck) { 
      //if we pass both checks, then do the rest of the logic 
      JOptionPane.showMessageDialog(null,"OUTPUT: Your age is " + age + " and Gender is " + gender); 

    } else { 
     //Write an error for invalid Gender 
     JOptionPane.showMessageDialog(null,"Error: Gender must be F or M") ; 
    } 

    } else { 
    //Write an error for invalid Age 
    JOptionPane.showMessageDialog(null,"Error: Age must be between 0 -100") ; 

    } 
} 

如果邏輯得到任何比較複雜，我建議重構隔離將年齡和性別分爲不同方法的邏輯。 （即使是這樣的代碼我也會這麼做，但這超出了你所問的範圍。）