Question

Write a java method that creates a two dimensional char array after asking the user to input a String text (for example, "Sara" which is entered by the user)  and String key consisting of integers (for example, 2314) only, such that

int rows=(int)Math.ceil(text.length()/key.length())+1;

int columns= key.length();

The method fills the 2d array with letters a String entered by the use (column by column). The method then shifts the columns of the array based on key.

For example, if the user enter 2 3 1 as key, then the columns of the array should start with the second, then third, and then first. After changing the columns, the method returns a String of all the characters in the 2d array but written row by row.

For example,

W R T

Y H J

using 2 3 1 is transformed into

R T W

H J Y >>>> The string becomes: RTWHJY

Answer 1

package test2;

import java.util.Scanner;

public class test {
   static Scanner in = new Scanner(System.in);
  
   static String shift(String text, String key)
   {
       try{
          
       int row = (int)Math.ceil(text.length()/key.length());
       int column = key.length();
       char Cmatrix[][] = new char[row][column];
       char CmatrixMod[][] = new char[row][column];
       String out = new String();
      
       int k = 0;
      
       for(int i = 0; i < row; i++)
           for(int j = 0; j < column; j++)
               Cmatrix [i][j] = text.charAt(k++);
      
       System.out.print("\nOriginal Matrix\n");
      
       for(int i = 0; i < row; i++){
           for(int j = 0; j < column; j++)
               System.out.print(Cmatrix [i][j]);
           System.out.print("\n");
       }
      
       System.out.print("\nTransformed Matrix\n");
      
       for(int i = 0; i < row; i++)
       {
           for(int j = 0; j < column; j++){
               int columnAt = Integer.parseInt(Character.toString(key.charAt(j))) - 1;
               CmatrixMod[i][j] = Cmatrix[i][columnAt];
               out = out + CmatrixMod[i][j];
               System.out.print(CmatrixMod[i][j]);
           }
           System.out.print("\n");
       }
      
       System.out.print("\n");
      
       return out;
      
       }catch(Exception e){
          
           return "Input Data Error";
      
       }
   }
   public static void main(String[] args) {
      
       String text = new String();
       String key = new String();
      
       System.out.print("Enter Text: ");
       text = in.nextLine();
       System.out.print("\nEnter key: ");
       key = in.nextLine();
      
       System.out.print(shift(text, key));
   }

}

//Alternate

package test2;

import java.util.Scanner;

public class test {
   static Scanner in = new Scanner(System.in);
  
   static String shift(String text, String key)
   {
       try{
          
       int row = (int)Math.ceil(text.length()/key.length());
       int column = key.length();
       char Cmatrix[][] = new char[row][column];
       String out = new String();
      
       int k = 0;
      
       for(int i = 0; i < row; i++)
           for(int j = 0; j < column; j++)
               Cmatrix [i][j] = text.charAt(k++);
      
       for(int i = 0; i < row; i++)
       {
           for(int j = 0; j < column; j++){
               int columnAt = Integer.parseInt(Character.toString(key.charAt(j))) - 1;
               out = out + Cmatrix[i][columnAt];
           }
       }
      
       return out;
      
       }catch(Exception e){
          
           return "Input Data Error";
      
       }
   }
   public static void main(String[] args) {
      
       String text = new String();
       String key = new String();
      
       System.out.print("Enter Text: ");
       text = in.nextLine();
       System.out.print("\nEnter key: ");
       key = in.nextLine();
      
       System.out.print(shift(text, key));
   }

}