Changing a string to an integer

Question

When I run the client and enter a number it is passed as a string. However it must be passed as an integer. How do I change this? and also change from while(true) to a do while so when the user enters "*" the program ends.

   while (true){
                   System.out.print("Enter a number ");
           String message = keyboard.nextLine(); 
           out.writeUTF(message); 
       }

http://stackoverflow.com/questions/5585779/converting-string-to-int-in-java — Can Celik, Mar 15 '16 at 19:51

score 0 · Answer 1 · edited May 23 '17 at 10:27

0

use int option = keyboard.nextInt();

seen here : if you want to know more

edited May 23 '17 at 10:27

Community

1
1

answered Mar 15 '16 at 19:49

osanger

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what do i change this line to? out.writeUTF(message); – JanetKeelan Mar 15 '16 at 19:53
@JanetKeelan what are you trying to say? – osanger Mar 15 '16 at 19:55
1

I got it sorted. Thank you – JanetKeelan Mar 15 '16 at 19:58

ΦXocę 웃 Пepeúpa ツ · Answer 2 · 2016-03-15T20:31:10.520

0

Try this: Scanner.nextInt() is giving back an integer...

Example

    final Scanner in = new Scanner(System.in);
    int number = 0;
    while(true){
            System.out.print("Enter a number ");
            number = in.nextInt();
            out.writeUTF(number);
    }

UPDATE:

if you need to do this in a loop until the user enter a specific key (e.g. "*") then:

final Scanner in = new Scanner(System.in);
String input = "";
do {
    System.out.print("Enter a number ");
    int numberParsed = 0;
    input = in.nextLine();
    try {
        numberParsed = Integer.parseInt(input);
        System.out.println(numberParsed);
        out.writeUTF(numberParsed);
    } catch (final NumberFormatException ex) {
        System.err.println("That input could not be parsed to integer....");
    }
} while (!input.equals("*"));

edited Mar 15 '16 at 20:31

answered Mar 15 '16 at 19:54

ΦXocę 웃 Пepeúpa ツ

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This works perfectly. Is it possible to change this into a do while now so that when a user enters "*" the program stops running? – JanetKeelan Mar 15 '16 at 20:15
yes, for sure, but the code must change a little... take a look at the update please – ΦXocę 웃 Пepeúpa ツ Mar 15 '16 at 20:31

score 0 · Answer 3 · answered Mar 15 '16 at 19:54

I imagine that keyboard is an object of type Scanner.

The Scanner has a method nextInt to retrieve the next integer.

Otherwise you can convert a string to an integer using the method Integer.parseInt as follow:

String message = keyboard.nextLine(); 
int myInt = Integer.parseInt(message);

score 0 · Answer 4 · answered Mar 15 '16 at 19:57

Instead of using nextLine and writeUTF, I would use nextInt (and hasNextInt allowing you terminate input with a non-int) with writeInt. Using a try-with-resources and a ByteArrayOutputStream for testing, that might look something like

Scanner keyboard = new Scanner(System.in);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (DataOutputStream out = new DataOutputStream(baos)) {
    System.out.print("Enter a number ");
    while (keyboard.hasNextInt()) {
        int v = keyboard.nextInt();
        out.writeInt(v);
        System.out.print("Enter a number ");
    }
} catch (IOException e) {
    e.printStackTrace();
}
System.out.println(Arrays.toString(baos.toByteArray()));

Changing a string to an integer

4 Answers4

UPDATE: