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

//
int main(int argc, string argv [])
{

// Check to make sure argc is not greater than 2
    if (argc != 2)
    {
        printf("Usage: ./caesar key\n");
        return 1;
    }

// Iterate through the charcherts in agrv and make sure they are all digits, if they are not print an error message and return 1

        for (int k = 0, n = strlen(argv[1]); k < n; k++)

             if (isdigit(argv[1][k]) == 0)
             {
                   printf("Usage: ./caesar key \n");
                   return 1;
              }

// Turn the string into int's

        int ato = atoi(argv[1]);

//check to make sure the key is not greater than 26

        if (ato > 26)
        {
           printf("Usage: ./caesar key \n");
           return 1;
        }

// Get a string from the user and store in the variable called plaintext, and then print ciphertext

        string plaintext = get_string("plaintext: ");
        printf("ciphertext: ");

// Iterate over in plain1 and if plain1 is less than the strlen of plaintext, print the character that plain1 will be at and add 1 to that character and also add one to plain1, print a newline and exit by returning 0.  That is if plain1 = 0, the 0th character in plaintext[plain1] will be h, if hello is enterted for plaintext.

        for (int p1 = 0; p1 < strlen(plaintext); p1++)

            if (p1 >= 65 && p1 = < 90)

                if (plaintext[p1]  + ato > 90)
                {
                    printf("%c", plaintext[p1]);
                }

                else
                {
                    printf("%c", plaintext[p1] + ato);
                }

              else if (p1 >= 97 && p1 =< 122)

                if (plaintext[p1]  + ato > 122)
                 {
                    printf("%c", plaintext[p1]);
                 }

               else
                {
                   printf("%c", plaintext[p1] + ato);
                }

               else printf("%c", plaintext[p1])