Program to Encrypt a String using ! and @

Given a string, the task is to encrypt this string using ! and @ symbols, alternatively. While encrypting the message the encrypted format must repeat the symbol as many times as the letter position in Alphabetical order.

Examples:

Input: string = "Ab" 
Output: !@@
Explanation:
Position of 'A' in alphabetical order is 1
and in String is odd position 
so encrypted message will have 1 '!'

Position of 'b' in alphabetical order is 2
and in String is even position 
so encrypted message will have 2 '@'

Therefore, the output "!@@"

Input: string = "CDE"
Output: !!!@@@@!!!!!

Approach: This is a very basic and simple type of Encryption technique and can be done as follows:  

• Get the character one by one from the String
• For each character, get the difference between the ASCII value of that character and ‘A'(if the character is a capital letter) or ‘a’ (if the letter is a small letter). This will be the number of times the encryption character is to be repeated.
• For the ith character of the string, if i is odd, the encryption character will be ‘!’ and if i is even, the encryption character will be ‘@’.

Below is the implementation of the above code: 

C++

// C++ program to Encrypt the String
// using ! and @
#include <bits/stdc++.h>
using namespace std;

// Function to encrypt the string
void encrypt(char input[100])
{

    // evenPos is for storing encrypting
    // char at evenPosition
    // oddPos is for storing encrypting
    // char at oddPosition
    char evenPos = '@', oddPos = '!';

    int repeat, ascii;

    for (int i = 0; i <= strlen(input); i++)
    {

        // Get the number of times the character
        // is to be repeated
        ascii = input[i];
        repeat = ascii >= 97 ? ascii - 96 : ascii - 64;

        for (int j = 0; j < repeat; j++)
        {

            // if i is odd, print '!'
            // else print '@'
            if (i % 2 == 0)
                cout << oddPos;
            else
                cout << evenPos;
        }
    }
}

// Driver code
int main()
{
    char input[100] = { 'A', 'b', 'C', 'd' };

    // Encrypt the String
    encrypt(input);
    return 0;
}

// This code is contributed by
// shubhamsingh10

C

// C program to Encrypt the String
// using ! and @

#include <stdio.h>
#include <string.h>

// Function to encrypt the string
void encrypt(char input[100])
{

    // evenPos is for storing encrypting
    // char at evenPosition
    // oddPos is for storing encrypting
    // char at oddPosition
    char evenPos = '@', oddPos = '!';

    int repeat, ascii;

    for (int i = 0; i <= strlen(input); i++) {

        // Get the number of times the character
        // is to be repeated
        ascii = input[i];
        repeat = ascii >= 97 ? ascii - 96 : ascii - 64;

        for (int j = 0; j < repeat; j++) {
            // if i is odd, print '!'
            // else print '@'
            if (i % 2 == 0)
                printf("%c", oddPos);
            else
                printf("%c", evenPos);
        }
    }
}

// Driver code
void main()
{
    char input[100] = { 'A', 'b', 'C', 'd' };

    // Encrypt the String
    encrypt(input);
}

Java

// Java program to Encrypt the String
// using ! and @
class GFG
{

// Function to encrypt the string
static void encrypt(char input[])
{

    // evenPos is for storing encrypting
    // char at evenPosition
    // oddPos is for storing encrypting
    // char at oddPosition
    char evenPos = '@', oddPos = '!';

    int repeat, ascii;

    for (int i = 0; i < input.length; i++)
    {

        // Get the number of times the character
        // is to be repeated
        ascii = input[i];
        repeat = ascii >= 97 ?
                  ascii - 96 : ascii - 64;

        for (int j = 0; j < repeat; j++)
        {
            // if i is odd, print '!'
            // else print '@'
            if (i % 2 == 0)
                System.out.printf("%c", oddPos);
            else
                System.out.printf("%c", evenPos);
        }
    }
}

// Driver code
public static void main(String[] args)
{
    char input[] = { 'A', 'b', 'C', 'd' };

    // Encrypt the String
    encrypt(input);
}
}

// This code is contributed by PrinciRaj1992

Python3

# Python3 program to Encrypt the String
# using ! and @

# Function to encrypt the string
def encrypt(input_arr) :

    # evenPos is for storing encrypting
    # char at evenPosition
    # oddPos is for storing encrypting
    # char at oddPosition
    evenPos = '@'; oddPos = '!';

    for i in range(len(input_arr)) :

        # Get the number of times the character
        # is to be repeated
        ascii = ord(input_arr[i]);
        repeat = (ascii - 96 ) if ascii >= 97 \
                               else (ascii - 64);

        for j in range(repeat) :

            # if i is odd, print '!'
            # else print '@'
            if (i % 2 == 0) :
                print(oddPos, end = "");
            else :
                print(evenPos, end = "");

# Driver code
if __name__ == "__main__" :

    input_arr = [ 'A', 'b', 'C', 'd' ];

    # Encrypt the String
    encrypt(input_arr);

# This code is contributed by AnkitRai01

C#

// C# program to Encrypt the String
// using ! and @
using System;
using System.Collections.Generic;

class GFG
{

// Function to encrypt the string
static void encrypt(char []input)
{

    // evenPos is for storing encrypting
    // char at evenPosition
    // oddPos is for storing encrypting
    // char at oddPosition
    char evenPos = '@', oddPos = '!';

    int repeat, ascii;

    for (int i = 0; i < input.Length; i++)
    {

        // Get the number of times the character
        // is to be repeated
        ascii = input[i];
        repeat = ascii >= 97 ?
                ascii - 96 : ascii - 64;

        for (int j = 0; j < repeat; j++)
        {
            // if i is odd, print '!'
            // else print '@'
            if (i % 2 == 0)
                Console.Write("{0}", oddPos);
            else
                Console.Write("{0}", evenPos);
        }
    }
}

// Driver code
public static void Main(String[] args)
{
    char []input = { 'A', 'b', 'C', 'd' };

    // Encrypt the String
    encrypt(input);
}
}

// This code is contributed by 29AjayKumar

Javascript

<script>

    // JavaScript program to Encrypt the
    // String using ! and @

    // Function to encrypt the string
    function encrypt(input)
    {

        // evenPos is for storing encrypting
        // char at evenPosition
        // oddPos is for storing encrypting
        // char at oddPosition
        let evenPos = '@', oddPos = '!';

        let repeat, ascii;

        for (let i = 0; i < input.length; i++)
        {

            // Get the number of times the character
            // is to be repeated
            ascii = input[i].charCodeAt();
            repeat = ascii >= 97 ?
                    ascii - 96 : ascii - 64;

            for (let j = 0; j < repeat; j++)
            {
                // if i is odd, print '!'
                // else print '@'
                if (i % 2 == 0)
                    document.write(oddPos);
                else
                    document.write(evenPos);
            }
        }
    }

    let input = [ 'A', 'b', 'C', 'd' ];

    // Encrypt the String
    encrypt(input);

</script>

Output:

!@@!!!@@@@

Time Complexity: O(n * 26), where n is the size of the given char array.
Auxiliary Space: O(1), no extra space is required, so it is a constant.

Approach 2: Using strings and index() method

C++

// C++ program to encrypt a string using ! and @ symbols
#include <iostream>
#include <string>
using namespace std;

int main()
{
    // Input string to be encrypted
    string str
        = "CDE"; // Define lowercase and uppercase alphabets
    string lower = "abcdefghijklmopqrstuvwxyz";
    string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    // Resultant string
    string res = "";

    // Iterate through the input string
    for (int i = 0; i < str.length(); i++) {
        // If the current index is even
        if (i % 2 == 0) {
            // If the current character is a lowercase
            // letter
            if (lower.find(str[i]) != string::npos) {
                // Append '!' to the resultant string as
                // many times as the position of the
                // character in the lowercase alphabet
                res += string(lower.find(str[i]) + 1, '!');
            }
            // If the current character is an uppercase
            // letter
            else {
                // Append '!' to the resultant string as
                // many times as the position of the
                // character in the uppercase alphabet
                res += string(upper.find(str[i]) + 1, '!');
            }
        }
        // If the current index is odd
        else {
            // If the current character is a lowercase
            // letter
            if (lower.find(str[i]) != string::npos) {
                // Append '@' to the resultant string as
                // many times as the position of the
                // character in the lowercase alphabet
                res += string(lower.find(str[i]) + 1, '@');
            }
            // If the current character is an uppercase
            // letter
            else {
                // Append '@' to the resultant string as
                // many times as the position of the
                // character in the uppercase alphabet
                res += string(upper.find(str[i]) + 1, '@');
            }
        }
    }

    // Print the encrypted string
    cout << res << endl;

    return 0;
}

Java

import java.util.*;

public class Main {

    public static void main(String[] args) {
        // Input string to be encrypted
        String str = "CDE";

        // Define lowercase and uppercase alphabets
        String lower = "abcdefghijklmopqrstuvwxyz";
        String upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        // Resultant string
        String res = "";

        // Iterate through the input string
        for (int i = 0; i < str.length(); i++) {
            // If the current index is even
            if (i % 2 == 0) {
                // If the current character is a lowercase letter
                if (lower.indexOf(str.charAt(i)) != -1) {
                    // Append '!' to the resultant string as many times as the position of the
                    // character in the lowercase alphabet
                    res += String.join("", Collections.nCopies(lower.indexOf(str.charAt(i)) + 1, "!"));
                }
                // If the current character is an uppercase letter
                else {
                    // Append '!' to the resultant string as many times as the position of the
                    // character in the uppercase alphabet
                    res += String.join("", Collections.nCopies(upper.indexOf(str.charAt(i)) + 1, "!"));
                }
            }
            // If the current index is odd
            else {
                // If the current character is a lowercase letter
                if (lower.indexOf(str.charAt(i)) != -1) {
                    // Append '@' to the resultant string as many times as the position of the
                    // character in the lowercase alphabet
                    res += String.join("", Collections.nCopies(lower.indexOf(str.charAt(i)) + 1, "@"));
                }
                // If the current character is an uppercase letter
                else {
                    // Append '@' to the resultant string as many times as the position of the
                    // character in the uppercase alphabet
                    res += String.join("", Collections.nCopies(upper.indexOf(str.charAt(i)) + 1, "@"));
                }
            }
        }

        // Print the encrypted string
        System.out.println(res);
    }
}

Python3

# Python3 program to Encrypt the String
# using ! and @
string = "CDE"
lower="abcdefghijklmopqrstuvwxyz"
upper="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
res=""
for i in range(0,len(string)):
    if(i%2==0):
        if(string[i] in lower):
            res+="!"*(lower.index(string[i])+1)
        else:
            res+="!"*(upper.index(string[i])+1)
    else:
        if(string[i] in lower):
            res+="@"*(lower.index(string[i])+1)
        else:
            res+="@"*(upper.index(string[i])+1)
print(res)

C#

// C# program to encrypt a string using ! and @ symbols
using System;

class Gfg
{
    static void Main(string[] args)
    {
        // Input string to be encrypted
        string str = "CDE";

        // Define lowercase and uppercase alphabets
        string lower = "abcdefghijklmopqrstuvwxyz";
        string upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

        // Resultant string
        string res = "";

        // Iterate through the input string
        for (int i = 0; i < str.Length; i++)
        {
            // If the current index is even
            if (i % 2 == 0)
            {
                // If the current character is a lowercase letter
                if (lower.Contains(str[i]))
                {
                    // Append '!' to the resultant string as
                    // many times as the position of the
                    // character in the lowercase alphabet
                    res += new string('!', lower.IndexOf(str[i]) + 1);
                }
                // If the current character is an uppercase letter
                else
                {
                    // Append '!' to the resultant string as
                    // many times as the position of the
                    // character in the uppercase alphabet
                    res += new string('!', upper.IndexOf(str[i]) + 1);
                }
            }
            // If the current index is odd
            else
            {
                // If the current character is a lowercase letter
                if (lower.Contains(str[i]))
                {
                    // Append '@' to the resultant string as
                    // many times as the position of the
                    // character in the lowercase alphabet
                    res += new string('@', lower.IndexOf(str[i]) + 1);
                }
                // If the current character is an uppercase letter
                else
                {
                    // Append '@' to the resultant string as
                    // many times as the position of the
                    // character in the uppercase alphabet
                    res += new string('@', upper.IndexOf(str[i]) + 1);
                }
            }
        }

        // Print the encrypted string
        Console.WriteLine(res);
    }
}

Javascript

// Javascript ptogram for the above approach

let string = "CDE";
let lower = "abcdefghijklmopqrstuvwxyz";
let upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let res = "";

for (let i = 0; i < string.length; i++) {
  if (i % 2 == 0) {
    if (lower.includes(string[i])) {
      res += "!".repeat(lower.indexOf(string[i]) + 1);
    } else {
      res += "!".repeat(upper.indexOf(string[i]) + 1);
    }
  } else {
    if (lower.includes(string[i])) {
      res += "@".repeat(lower.indexOf(string[i]) + 1);
    } else {
      res += "@".repeat(upper.indexOf(string[i]) + 1);
    }
  }
}

console.log(res);

// This code is contributed by codebraxnzt

Output

!!!@@@@!!!!!

Time Complexity: O(n * 26), where n is the length of the given string.
Auxiliary Space: O(n * 26)