Alexandr6363

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

//prototype
string valid_key(string key);
string do_text(string start_text, string key);
void swap(char *a, char *b);

ThatOneCubanDude

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

int main(int argc, string argv[])
{
    //checks if user has inputed a command line argument, if not returns error message
    if (argc == 2)