cipher.cpp

#include<iostream>
#include<cstdlib>
#include<cstring>

using namespace std;
char* encrypt(const char* message, const int count, char* cipher, const int cipher_count);
char* decrypt(const char* cipher, const int count, char* plain, const int plain_count);
const char alpha[28] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ ";
const char specialChars[28] = {
        '-', '!', '+', '\\', '~', '@', '^', '$', '[', '/',
        '>', ']', '#', '}', '(', '%', '*', '<', '}', '&',
        ')', ' ', ';', '|', ':', ',', '"','\0' // Space at index 21, quote at index 26
};


int main()
{
    /*for (int i = 0; i < 28; i++)
    {
        if (alpha[i] == '\0')
            break;

        cout << alpha[i] << " - "<<specialChars[i]<<endl;
    }*/

    char message[10000] = { '\0' };
    char cipher[10000] = { '\0' };
    char plain[10000] = { '\0' };
    cout << "Enter the message to be encrypted: ";
    cin.getline(message, 10000);
    int count = strlen(message);
    encrypt(message, count,cipher,10000);

    cout << endl;
    for (int i = 0; i < count; i++)
    {
        cout << cipher[i];
    }
    cout << endl;

    decrypt(cipher, count, plain, 10000);
    for (int i = 0; i < count; i++)
    {
        cout << plain[i];
    }
    cout << endl;
    return 0;
}

char* encrypt(const char* message, const int count,char *cipher,const int cipher_count)
{
    char msg = '\0';
    for (int i = 0; i < count; i++)
    {
        for (int j = 0; j < 28; j++)
        {
            if (message[i] == '\0')
                break;
            if (message[i] >96)
            {
                msg = message[i] - ('a' - 'A');
            }
            else
            {
                msg = message[i];
            }


            if (msg == alpha[j])
            {
                cipher[i] = specialChars[j];
                break;
            }
        }
    }
    return cipher;
}

char* decrypt(const char* cipher, const int count, char* plain, const int plain_count)
{
    char cip = '\0';
    for (int i = 0; i < count; i++)
    {
        for (int j = 0; j < 28; j++)
        {
            if (cipher[i] == '\0')
                break;
            cip = cipher[i];


            if (cip == specialChars[j])
            {
                plain[i] = alpha[j];
                break;
            }
        }
    }
    return plain;
}