how to convert string to int in Java

Question

I'm working on Caesar cipher example in which I want that it get different keys from user and finally one key decrypt the original text , but I got a problem, here is my code

public static void main(String[] args) {
    Scanner user_input= new Scanner(System.in);
    String plainText = "University of malakand";
    String key;
    key = user_input.next();

    Ceasercipher cc = new Ceasercipher();

    String cipherText = cc.encrypt(plainText,key);
    System.out.println("Your Plain  Text :" + plainText);
    System.out.println("Your Cipher Text :" + cipherText);

    String cPlainText = cc.decrypt(cipherText,key);
    System.out.println("Your Plain Text  :" + cPlainText);
}

it shows an error on this line

    String cipherText = cc.encrypt(plainText,key);

it shows me error on key incompatible types:

String cannot be converted into int

What can I do?

First, what does `String cannot be converted into int` mean to you? — Sotirios Delimanolis, Apr 20 '14 at 05:01
You did not think it necessary to show what value you entered ? — Erran Morad, Apr 20 '14 at 05:05

score 2 · Answer 1 · answered Apr 20 '14 at 05:07

Ask following questions to your self first.

What your method want as parameter?
Why both are Incompatible?
What String cipherText = cc.encrypt(plainText,key); mean?
key is String or int?

Use methods like Integer.parseInt(String value) or Integer.valueOf(String value) for conversion.

score 1 · Answer 2 · answered Apr 20 '14 at 05:03

1

It seems like you need to convert a String to int, not a int to String. To do that, you can use Integer.parseInt():

int someInt = Integer.parseInt(someString);

answered Apr 20 '14 at 05:03

Christian Tapia

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score 0 · Answer 3 · edited Apr 20 '14 at 05:09

0

Try this -

String cipherText = cc.encrypt(plainText,Integer.parseInt(key));

edited Apr 20 '14 at 05:09

Erran Morad

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answered Apr 20 '14 at 05:04

Amit

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score 0 · Answer 4 · answered Apr 20 '14 at 05:05

You are passing String and the method parameter seems to have int and hence the error. You might want to convert your string to int using int keyInt = Integer.parseInt(key); and similarly for plain text if necessary and then pass keyInt and/or plainTextInt as the parameters.

how to convert string to int in Java

4 Answers4