Vigenere code not giving correct output when the key is a mix of upper & lower case letters!

Question

currently doing the vigenere code & have gotten the green light on all but one of the checks. The check it is failing is the case when the key is 'BaZ' and the word is 'CaQGon'.

The message given is;

:( encrypts "BaRFoo" as "CaQGon" using "BaZ" as keyword \ expected output, but not "ciphertext: C=gQKGuhn\n"

i've also tried my key to be 'aBc' & the word to be encrypted be 'abc' & the output given is 'ag[ek' , my code works fine if the k value is all lower case letters or all upper case letters - it's more so if the k value is a mix of upper and lower case letters.

I've tried to define cases where the code word is lower case and the key is upper & vice versa, but have been unsuccessful in fixing this problem! Any tips as to where the code needs to be touched would be much appreciated!

The code is listed belooooow.

Cheers.

#include <stdio.h>
#include <cs50.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

int main(int argc, string argv[])
{
    // code is the string the user will be inputting
    string k;
    string code;
    k = argv[1];

    // case where only one argument is put in command line!
    if (argc == 1)
    {
        code = "need dat code value in the command line";
        k = ".";
        printf("%s%s\n", code, k);
        return 1;
    }

    // case where more than two arguments are put in the command line!
    if (argc > 2)
    {
        code = "too many argssssss";
        k = ".";
        printf("%s%s\n", code, k);
        return 1;
    }

    // correct amount of arguments
    if (argc == 2)
    {

        // checking if string inputted is a word
        for (int p = 0; p < strlen(argv[1]); p++)
        {
            if (!isalpha(argv[1][p]))
            {
            printf("not a word!\n");
            return 1;
            }
        }
        // getting codeword input from user
        printf("plaintext: ");
        code = get_string();

        // defining a few arrays which will help with encryption
        int l = 0;
        int j = 0;
        int kl;
        kl = strlen(k);
        int ncode[strlen(code)];
        int num[strlen(code)];

        printf("ciphertext: ");

        // loop to get shiz going
        for (int i = 0, n = strlen(code); i < n; i++)
        {
            // for code letter being an uppercase letter
            if (isupper(code[i]))
            {
                    if (isupper(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'A';
                        num[i] = ((ncode[i] + (argv[1][(i - j)%kl] - 'A')))%26;
                        printf("%c", num[i] + 'A');
                        l++;
                    }

                    if (islower(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'A';
                        num[i] = (ncode[i] + (argv[1][(i - j)%kl] - 'a'))%26;
                        printf("%c", num[i] + 'A');
                        l++;
                    }
            }

            // for code letter being a lowercase letter
            if (islower(code[i]))
            {
                    if (islower(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'a';
                        num[i] = ((ncode[i] + (argv[1][(i - j)%kl] - 'a')))%26;
                        printf("%c", (num[i] + 'a'));
                        l++;
                    }

                    if (isupper(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'a';
                        num[i] = (ncode[i] + (argv[1][(i - j)%kl] - 'A'))%26;
                        printf("%c", (num[i] + 'a'));
                        l++;
                    }
            }

            if (code[i] < 'A' || (code[i] > 'Z' && code[i] < 'a') || code [i] > 'z') 
            {
            printf("%c", code[i]);
            j++;
            l++;
            }
        }

    printf("\n");

    }
}

Answer 1

Ended up reading a similar question & found the problem from this question:

cs50 pset2/vigenere - code doesn't work if text and key differ upper/lower case

problem was this case:

"Finally, when a letter is encoded, j is incremented. But consider what happens when the key letter is uppercase and the next key char is lower case. Because j is incremented when the first test case is processed, both tests for the key will be true, so both cases will be executed. Maybe an else if should be considered?"

So changed code to include else if conditions; code now works as needed!

include

#include <cs50.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

int main(int argc, string argv[])
{
    // code is the string the user will be inputting
    string k;
    string code;
    k = argv[1];

    // case where only one argument is put in command line!
    if (argc == 1)
    {
        code = "need dat code value in the command line";
        k = ".";
        printf("%s%s\n", code, k);
        return 1;
    }

    // case where more than two arguments are put in the command line!
    if (argc > 2)
    {
        code = "too many argssssss";
        k = ".";
        printf("%s%s\n", code, k);
        return 1;
    }

    // correct amount of arguments
    if (argc == 2)
    {

        // checking if string inputted is a word
        for (int p = 0; p < strlen(argv[1]); p++)
        {
            if (!isalpha(argv[1][p]))
            {
            printf("not a word!\n");
            return 1;
            }
        }
        // getting codeword input from user
        printf("plaintext: ");
        code = get_string();

        // defining a few arrays which will help with encryption
        int l = 0;
        int j = 0;
        int kl;
        kl = strlen(k);
        int ncode[strlen(code)];
        int num[strlen(code)];

        printf("ciphertext: ");

        // loop to get shiz going
        for (int i = 0, n = strlen(code); i < n; i++)
        {
            // for code letter being an uppercase letter
            if (isupper(code[i]))
            {
                    if (isupper(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'A';
                        num[i] = ((ncode[i] + (argv[1][(i - j)%kl] - 'A')))%26;
                        printf("%c", num[i] + 'A');
                        l++;
                    }

                    else if (islower(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'A';
                        num[i] = (ncode[i] + (argv[1][(i - j)%kl] - 'a'))%26;
                        printf("%c", num[i] + 'A');
                        l++;
                    }
            }

            // for code letter being a lowercase letter
            if (islower(code[i]))
            {
                    if (islower(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'a';
                        num[i] = ((ncode[i] + (argv[1][(i - j)%kl] - 'a')))%26;
                        printf("%c", (num[i] + 'a'));
                        l++;
                    }

                    else if (isupper(argv[1][(l - j)%kl]))
                    {
                        ncode[i] = code[i] - 'a';
                        num[i] = (ncode[i] + (argv[1][(i - j)%kl] - 'A'))%26;
                        printf("%c", (num[i] + 'a'));
                        l++;
                    }
            }

            if (code[i] < 'A' || (code[i] > 'Z' && code[i] < 'a') || code [i] > 'z') 
            {
            printf("%c", code[i]);
            j++;
            l++;
            }
        }

    printf("\n");

    }
}