The code is compiling but it is not giving the expected output.

Code:

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import java.util.Scanner;


public class ProjectTools {
        public static void main(String[] args){
               
                Scanner scan = new Scanner(System.in);
                System.out.println("Enter the key");
                        int key = scan.nextInt();
               
                        System.out.println("Enter the text");
                        String text = scan.next() ;
                        String x = "aa";
                       
                        String ciphertext = encrypt( text , key);
                        System.out.println("ciphertext" + ciphertext);
                }
        private static String encrypt(String str , int key){
               
                if (key < 0)
                {
                        key = 26-(-key%26);
                }
                String result = "" ;
                for (int i = 0 ; i<str.length() ; i++){
                        char ch = str.charAt(i);
                        result+= encryptchar(ch, key);
                       
                }
                      return result;
        }
  private static char encryptchar(char ch , int key){
          if (Character.isUpperCase(ch))
          {
                return ((char) ( 'A'+ ((ch-'A'+key)%26)));
                 
          }
          return ch ;
       
         
  }
               
        }

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You forgot to tell us what output you expect, and what you get.

Also, go through Code Conventions for the Java Programming Language: Contents -- your indenting is all over the place.


db

input:
aaa
output:
aaa
but i expect from my code ddd.

Describe what you expect your encryptchar(char ch , int key) to return when ch isn't an uppercase letter.

db

I figure that out.
Thank you.

The following line should be ( 'A'+ ((ch-'A'+key)%26)));

( 'A'+ ((-6 +ch-'A'+key)%26))); if you plug it in the code it will run, and you can try different inputs.
Thanks.