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Find letter’s position in Alphabet using Bit operation
  • Difficulty Level : Expert
  • Last Updated : 18 May, 2021

Given a string of English alphabets. The task is, for every character in the string print its position in the English alphabets.
Note: The characters in the string are considered to be case-insensitive. That is, both ‘A’ and ‘a’ is at the first position.
Examples: 
 

Input: “Geeks” 
Output: 7 5 5 11 19 
‘G’ is the 7th character of the alphabets 
‘e’ is the 5th and so on…
Input: “Algorithms” 
Output: 1 12 7 15 18 9 20 8 13 19 
 

 

Approach: 
A letter’s position in Alphabet can easily be found by performing logical AND operation with the number 31.
Note that this is only applicable to letters and not special characters.
Every letter has an ASCII value which can be represented in binary form. Performing the bitwise and of this value with the number 31 will give the letter’s position in the alphabets.
Below is the implementation of the above approach:
 

C++




// C++ implementation of the approach
#include <iostream>
using namespace std;
 
const int NUM = 31;
 
// Function to calculate the position
// of characters
void positions(string str, int n)
{
    for (int i = 0; i < n; i++) {
 
        // Performing AND operation
        // with number 31
        cout << (str[i] & NUM) << " ";
    }
}
 
// Driver code
int main()
{
    string str = "Geeks";
    int n = str.length();
 
    positions(str, n);
 
    return 0;
}

Java




// Java implementation of the approach
public class GFG {
 
    public static final int NUM = 31;
 
    // Function to calculate the position
    // of characters
    static void positions(String str, int n)
    {
        for (int i = 0; i < n; i++) {
 
            // Performing AND operation
            // with number 31
            System.out.print((str.charAt(i) & NUM) + " ");
        }
    }
 
    // Driver code
    public static void main(String[] args)
    {
        String str = "Geeks";
        int n = str.length();
        positions(str, n);
    }
}

Python




# Python3 implementation of the approach
  
NUM = 31
  
# Function to calculate the position
# of characters
def positions(str):
    for i in str:
          
        # Performing AND operation
        # with number 31
        print((ord(i) & NUM), end =" ")
  
# Driver code
str = "Geeks"
positions(str)

C#




// C# implementation of the approach
using System;
 
class GFG {
 
    public static int NUM = 31;
 
    // Function to calculate the position
    // of characters
    static void positions(string str, int n)
    {
        for (int i = 0; i < n; i++) {
 
            // Performing AND operation
            // with number 31
            Console.Write((str[i] & NUM) + " ");
        }
    }
 
    // Driver code
    public static void Main()
    {
        string str = "Geeks";
        int n = str.Length;
        positions(str, n);
    }
}
 
// This code is contributed by AnkitRai01

PHP




<?php
// PHP implementation of the approach
 
// Function to calculate the position
// of characters
function positions($str, $n)
{
    $a = 31;
    for ($i = 0; $i < $n; $i++)
    {
 
        // Performing AND operation
        // with number 31$
        print((ord($str[$i])&($a))." ");
    }
}
 
// Driver code
$str = "Geeks";
$n = strlen($str);
positions($str, $n);
 
// This code is contributed by 29AjayKumar
?>

Javascript




<script>
 
      // JavaScript implementation of the approach
      const NUM = 31;
 
      // Function to calculate the position
      // of characters
      function positions(str, n)
      {
        for (i = 0; i < n; i++)
        {
          // Performing AND operation
          // with number 31
          document.write((str[i].charCodeAt(0) & NUM) +
          " ");
        }
      }
 
      // Driver code
      var str = "Geeks";
      var n = str.length;
      positions(str, n);
       
</script>
Output: 
7 5 5 11 19

 

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