if (_user_text[i] == _alphabet[j])

void uppgift_2() {

    // Uppgift:
    // Du skall skapa en enkel kryptering. Låt användaren mata in en text av typen string, valfri storlek.
    // Skriv sedan ut en krypterad version av strängen med rot3.

    // Array with the alphabet in it
    char alphabet[36] = { 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',
                            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};

    // Variables
    std::string user_text = "", org_string = "";
    std::string temp = "";
    int rot_x = 7; // rot7

    // Prompt user for input
    std::cout << "| Enter in a random text (english): ";
    getline(std::cin, user_text);
    org_string = user_text;

    // Make string lowercase
    for (unsigned int b = 0; b < user_text.length(); b++) {
        char lower_Version = tolower(user_text[b]);
        temp += lower_Version;
    }
    user_text = temp;

    // Encrypting user entered text...
    std::string _encrypted_text = encrypt_string(user_text, alphabet, rot_x);

    // Prints out the original string, the encrypted version and the final decrypted version
    std::cout << "n| Original version: " << org_string << std::endl;
    std::cout << "| - - - - - - - - - - - - - - - - - - - - - - - - - - - |n" << std::endl;
    std::cout << "| Encrypted version: " << _encrypted_text << std::endl;
    std::cout << "| Decrypted version: " << decrypt_string(_encrypted_text, alphabet, rot_x) << "nn";

    system("PAUSE");
    main_menu(); // Sends the user back to the main menu

}

std::string encrypt_string(std::string &_user_text, char(&_alphabet)[36], int &rot_x) {

    // Variable(s)
    std::string encrypted_text = "";
    int array_len = 35;
    int pointer = 0; // Used to determine if a switch from rot7 to rot13 is needed

    // The outer loop goes through each character of the user entered string
    for (int i = 0; encrypted_text.length() < _user_text.length(); i++) {
        // The inner loop finds the correspondent character from the alphabet and uses rot7 or rot13 on it
        for (int j = 0; j <= array_len; j++) {
            // if (selected character from user string) is equal to (the correspondant character in the alphabet)
            if (_user_text[i] == _alphabet[j]) {
                int alphabet_index = (j + rot_x);
                // Checks if alphabet_index is out of range and adjusts accordingly
                if (alphabet_index >= array_len+1) {
                    alphabet_index -= array_len+1;
                }
                // Saves the decrypted character...
                char encrypted_char = _alphabet[alphabet_index];
                // ... and concatenates it to the decrypted string
                encrypted_text += encrypted_char;
                break; // Breaks out of inner loop and lets outer loop get the next character
            }
        }
        pointer++;
        // If five characters have been encrypted, switch to rot13
        if (pointer == 5) {
            rot_x = 13;
        }
        // Go back to rot7 when yet another 5 characters have been encrypted
        else if (pointer == 10) {
            rot_x = 7;
            pointer = 0; // Reset the pointer
        }
    }

    // Returns the final encrypted text
    return encrypted_text;

}