如何获取用户输入的int数并同时存储用户的输入？

Question

this program is a magic date program (day times month="year as a two digits number") like 06\\10\\60 ... I want to make a condition ... if the day or the month or the year entered are more or less than 2 digits should display an error message ... I tried this

 System.out.println("Please enter the day as a two digit Number");
 day=key.nextInt();
 day1=day.length();

but it did not work ... so I tried this :

System.out.println("Please enter the month as a two digit Number");
month1=key.next().length();
month=key.nextInt();

but when i run the program ... it requires two inputs not one So help me out

Answer 1

Simply:

day = key.nextInt();
int dayAbs = Math.abs(day);      // to handle negatives
if(dayAbs >= 10 && dayAbs <= 99) {
    // ...
}

Answer 2

The problem is that you are using nextInt() but you would like two-digit numbers like 06 which is not a valid integer.

It will be better to:

1. Scan the input as a String. String day = scan.nextLine();

2. Validate for correct input by using day.matches("\\\\d{2}")
   (This will only match any pairing of [0-9] and don't have to worry about other characters)

3. If it Validates then you can get your Integer: Integer realDay = Integer.valueOf(day);

4. Perform further Validation to test the range (1-31 for Days) (1-12 for Months) (1-28 or 1-29 for February depending on the Year) etc.

Answer 3

You can do this simply by converting int to string and then by checking the length of the string.

String s = Integer.toString(day);
if(s.length() <= 2 && !(s.length() < 1)){
    System.out.println("Good");
}else
    System.out.println("Bad"); 

Answer 4

to test for the number of digits in an int primitive try this

int number = ...;
// or however you get the number

int length = (int)(Math.log10(number)+1);

if(length!=2) {
    // no!
} else {
    // yuss!
}

Answer 5

Except using int use string then check the length of the input. This code is only a base. It is stored in result. Then after the check use Integer.parseInt(result);

System.out.println("Please enter two digits:");
    Scanner scan = new Scanner(System.in);
    String result = scan.next();
     if(result.length()>2 || result.length()<2)
         System.out.println("ERROR");
     else
         System.out.println("Success");

Answer 6

Actually, it seems that you want to enforce the length of the string so that the user has to type 06 instead of 6 .

If so:

String dayString = key.next();
if(dayString.length() != 2) {
    // throw error
}
int day = Integer.parseInt(dayString);

Answer 7

int day=key.nextInt();
String dayString = "";
if(day> 30 || day <0){ System.out.println("Error1");}
else if(day<10 ){ dayString = "0" + String.valueOf(day);}
else{dayString = String.valueOf(day);}

here u have ur day in 2 digits as a string,more easy to manipulate. u can also try Date class (java.util.Date)

Answer 8

i don't understand that why you are using key but i think that Buffer reader can solve your problem here is the example!

int month=0,length=0;
        String len=null;
        BufferedReader bf=new BufferedReader(new InputStreamReader(System.in));
        System.out.println("Please enter the month as a two digit Number");
        len=bf.readLine();
        length=len.length();
        month=Integer.parseInt(len);
        if(length==2)
        {
            System.out.println("Here you go month is two digit!");
        }
        else
        {
           //inform user that month is not 2 digits!
        }