Why it doesn't show me first two letters of firstname and last two of lastname?

Question

I tried recently to build an app that shows you a generated text using the first two letters from your firstname, and last two letters from lastname but it doesn't work.

import java.util.Scanner;
    public class HW2ex2 {
        public static void main (String[] args) {
            Scanner scan = new Scanner(System.in);
            
            String firstName, lastName, yourCNP;
    
            System.out.println("Enter your first name: ");
            firstName = scan.nextLine();
            System.out.println("Enter your last name: ");
            lastName = scan.nextLine();
            System.out.println("Enter your CNP: ");
            yourCNP = scan.nextLine();
    
            firstName = firstName.toLowerCase();
            lastName = lastName.toUpperCase();
            
            String firstPart = String.valueOf(firstName.charAt(0) + firstName.charAt(1));
        
            String secondPart = String.valueOf(lastName.charAt(lastName.length() - 2) + lastName.charAt(lastName.length() - 1));
    
            String password = firstPart + secondPart;
    
            System.out.println("Your password is: " + password);
    
            scan.close();
    
        }
    }

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score 1 · Answer 1 · answered Oct 18 '22 at 15:06

String.valueOf(firstName.charAt(0) + firstName.charAt(1))

does something very different to what you expect. It first adds the two characters numerically based on their ASCII value: 'a' + 'a' = 97 + 97 = 194. The valueOf then simply converts that to a String: "194".

Rather than doing that you should use substring or use a trick to force string concatenation rather than integer addition:

"" + firstName.charAt(0) + firstName.charAt(1)

Identical logic for the secondPart obviously.

Why it doesn't show me first two letters of firstname and last two of lastname?

1 Answers1