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

string get_input()
{
    string plain = get_string("plaintext: ");
    return plain;
}

int caesar_cipher(string s, int k)
{
    printf("ciphertext: ");
    string cipher;
    int SIZE = strlen(s);
    for (int i = 0; i < SIZE; i++)
    {
        // Creates a place to store the ciphered value
        int c_key;
        if ( isupper(s[i]) )
        {
            c_key = ((int) s[i] - 'A' + k) % 26 + (int) 'A';
        } else if ( islower(s[i]) )
        {
            c_key = ((int) s[i] - 'a' + k) % 26 + (int) 'a';
        } else {
            c_key = (int) s[i];
        }

        // Prints the (char) -> int s[i] + 1;
        printf("%c", (char) c_key);
    }
    printf("\n");
    return 0;
}

int main(int argc, string argv[])
{
    if ((argc > 1 && argc < 3))
    {
        // Stores key
        int k = atoi(argv[1]);
        // Gets plaintext
        string plain = get_input();
        // Cracks it up
        caesar_cipher(plain, k);
    } else
        {
            printf("Usage: ./caesar key\n");
            return 1;
        }
}