Encode given string by shifting each character forward with its alphabetical value

Last Updated : 27 Jun, 2023

Given string str of size N consisting of lowercase English alphabets, the task is to encode the given string as follows:

change every character of that string to another character
the distance between the changed character and the current character is the same as the distance between the current character and ‘a’.
Also, assume that the character’s array forms a cycle, i.e. after ‘z’ the cycle starts again from ‘a’.

Examples:

Input: str = “geeksforgeeks”
Output: “miiukkcimiiuk”
Explanation:
g changed to m (distance between g & a is 6, distance between m & g is 6)
e changed to i (distance between e & a is 4, distance between i & e is 4)
and same for other characters as well.

Input: str = “cycleofalphabet”
Output: “ewewickaweoacim”

Approach: This problem can be solved using the following steps:

Run a loop from i=0 to i<N and traverse each character of the string. For each character str[i]:
- Find the distance between str[i] and ‘a’, i.e. dist=str[i]-‘a’.
- Now, if (dist+(str[i]-‘a’)) > 26, this means that ‘z’ is exceeded, so
Otherwise, change str[i] to str[i]+dist.
Print the string as the answer to this problem.

Below is the implementation of the above approach:

C++

// C++ code for the above approach
#include <bits/stdc++.h>
using namespace std;
 
// Function to change every character
// of the string to another character
void changeString(string str)
{
    for (auto& x : str) {
        int dist = x - 'a';
 
        // If 'z' is exceeded
        if (dist + (x - 'a') >= 26) {
            dist = (dist + (x - 'a')) % 26;
            x = 'a' + dist;
        }
 
        // If 'z' is not exceeded
        else {
            x = x + dist;
        }
    }
    cout << str << endl;
}
 
// Driver Code
int main()
{
    string str = "nayan";
    changeString(str);
    return 0;
}

Java

// Jsvs code for the above approach
import java.util.*;
 
class GFG {
 
  // Function to change every character
  // of the string to another character
  static void changeString(String str)
  {
    char[] ch = str.toCharArray();
    for (int i = 0; i < str.length(); i++) {
      int dist = ch[i] - 'a';
 
      // If 'z' is exceeded
      if (dist + (ch[i] - 'a') >= 26) {
        dist = (dist + (ch[i] - 'a')) % 26;
        ch[i] = (char)('a' + dist);
      }
 
      // If 'z' is not exceeded
      else {
        ch[i] = (char)(ch[i] + dist);
      }
    }
 
    String s = new String(ch);
    System.out.println(s);
  }
 
  // Driver Code
  public static void main(String[] args)
  {
    String str = "cycleofalphabet";
    changeString(str);
  }
}
 
// This code is contributed by ukasp.

Python3

# Python code for the above approach 
 
# Function to change every character
# of the string to another character
def changeString(str):
    str = list(str)
    for x in range(len(str)):
        dist = ord(str[x]) - ord('a')
 
        # If 'z' is exceeded
        if (dist + (ord(str[x]) - ord('a')) >= 26):
            dist = (dist + (ord(str[x]) - ord('a'))) % 26;
            str[x] = chr(ord('a') + dist);
         
 
        # If 'z' is not exceeded
        else:
            str[x] = chr(ord(str[x]) + dist);
         
    str = "".join(str)
    print(str)
 
# Driver Code
 
str = "cycleofalphabet";
changeString(str);
 
# This code is contributed by Saurabh Jaiswal

C#

// C# code for the above approach
using System;
using System.Collections;
 
class GFG
{
 
  // Function to change every character
  // of the string to another character
  static void changeString(string str)
  {
    char[] ch = str.ToCharArray();  
    for(int i = 0; i < str.Length; i++) {
      int dist = ch[i] - 'a';
 
      // If 'z' is exceeded
      if (dist + (ch[i] - 'a') >= 26) {
        dist = (dist + (ch[i] - 'a')) % 26;
        ch[i] = (char)('a' + dist);
      }
 
      // If 'z' is not exceeded
      else {
        ch[i] = (char)(ch[i] + dist);
      }
    }
 
    string s = new string(ch);
    Console.WriteLine(s);
  }
 
  // Driver Code
  public static void Main()
  {
    string str = "cycleofalphabet";
    changeString(str);
  }
}
 
// This code is contributed by Samim Hossain Mondal.

Javascript

<script>
      // JavaScript code for the above approach 
 
      // Function to change every character
      // of the string to another character
      function changeString(str) {
          str = str.split('')
          for (let x = 0; x < str.length; x++) {
              let dist = str[x].charCodeAt(0) - 'a'.charCodeAt(0);
 
              // If 'z' is exceeded
              if (dist + (str[x].charCodeAt(0) - 'a'.charCodeAt(0)) >= 26) {
                  dist = (dist + (str[x].charCodeAt(0) - 'a'.charCodeAt(0))) % 26;
                  str[x] = String.fromCharCode('a'.charCodeAt(0) + dist);
              }
 
              // If 'z' is not exceeded
              else {
                  str[x] = String.fromCharCode(str[x].charCodeAt(0) + dist);
              }
          }
          str = str.join('')
          document.write(str + "<br>")
      }
 
      // Driver Code
 
      let str = "cycleofalphabet";
      changeString(str);
 
     // This code is contributed by Potta Lokesh
  </script>