CODEWITHSUNDEEP
java
Alberto Lopez Rodriguez
Alberto Lopez Rodriguez

Reputation: 57

How can I set limits on how many characters can be inputted? (Java)

do{
        out.println("\n---------------------------------");
        out.println("---------------------------------");
        out.print("Please type your acces card number: ");

    try{
        card = input.nextInt();

        if(card.length != 10){
            out.println("The number you typed is incorrect");
            out.println("The number must be 10 numbers long");
        continue;
            }
        }   

        catch(InputMismatchException ex){
            }
    }while(true);

Im trying to make card be 10 characters long. Like (1234567890), and if the user inputs (123) or (123456789098723) an error message should appear. card.length doesnt seem to work.

Upvotes: 3

Views: 259

Answers (4)

Shadow
Shadow

Reputation: 4006

You cannot get the length of an int. It would be much better to get input as a String, and convert it into an int later on, if the need arises. You can do the error checking in your while loop, and if you like short circuiting, you can have the while check display your error message too:

out.println("\n---------------------------------");
out.println("---------------------------------");
out.print("Please type your access card number: ");

do {
    try {
        card = input.nextLine();
    } catch (InputMismatchException ex) {
        continue;
    }
} while ( card.length() != 10 && errorMessage());

And have your errorMessage function return true, and display the error messages:

private boolean errorMessage()
{
    out.println("The number you typed is incorrect");
    out.println("The number must be 10 numbers long");
    return true;
}

Upvotes: 0

Elliott Frisch
Elliott Frisch

Reputation: 201447

You could change

if(card.length != 10){

to something like

if(Integer.toString(card).length() != 10){

Of course, it's possible the user entered

0000000001

which would be the same as 1. You could try

String card = input.next(); // <-- as a String

then

if (card.length() == 10)

and finally

Integer.parseInt(card)

Upvotes: 3

Greg
Greg

Reputation: 1243

In Java, you cannot get the length of an int. The easiest way to find the number of digits is to convert it to a String. However, you can also do some math to find out the number's length. You can find more information here.

Upvotes: 0

Pham Trung
Pham Trung

Reputation: 11284

Just change int to String

   String card = input.next();
   if(card.length() != 10){
      //Do something
   }

You can easily convert it to int later

   int value = Integer.parseInt(card);

Upvotes: 3

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