CS50 Pset02 (3 parts)

caesar.c

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

int main(int argc, string argv[])
{
    int i = 0;
    int stringlength = 0;
    
    if (argc > 2 || argc <2)
        {
            printf("Please try again. Input the command and your cipher number.\n");
            return 1;
        }
        else
        {
        //printf("Please provide me with a string (series of words) to encrypt. I will encrypt using the ceasar cypher and the number you have already provided:\n");
        string stringtoencrypt = GetString();
        int key = atoi(argv[1]);

            for ( i = 0, stringlength = strlen(stringtoencrypt); i < stringlength; i++)
            {
                if (isalpha(stringtoencrypt[i]))
                {
                    
                    if (isupper(stringtoencrypt[i]))
                    {
                       int letter = (((stringtoencrypt[i] + key - 65) % 26 ) + 65);
                       printf("%c", letter);
                    }
                     if (islower(stringtoencrypt[i]))
                    {
                    int letter = (((stringtoencrypt[i] + key - 97) % 26 ) + 97);
                       printf("%c", letter);
                    }
    
                }

                 else
                    {
                        printf("%c", stringtoencrypt[i]);
                    }
            }
            
        printf("\n");
        }
}
    
    
//made by tyler loeper for CS50 2016

initials.c

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

int main(void)
{
    string fullname;
    //printf("Please write your full name.\n");
    fullname = GetString();
    //strupr (fullname);
    
    int stringlength = strlen(fullname);
    //printf("Your name is %s\n", fullname);
    
    for (int i = 0; i < stringlength; i++)
    
        {
        if (i == 0)
        {
            char lettertoprint = fullname[i];
            lettertoprint = toupper(lettertoprint);
            printf("%c", lettertoprint);
        }
        
       else if (fullname[i] == ' ')
       {
            //printf("%c", fullname[i+1]);
            char lettertoprint = fullname[i+1];
            lettertoprint = toupper(lettertoprint);
            printf("%c", lettertoprint);
            
       }
            
        }
        
    printf("\n");
    //printf("\n Those are your initials are BLANK\n");
}

//made by tyler loeper for CS50 2016

vigenere.c

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

int main(int argc, string argv[])
{
    //define all variables
    int i = 0;
    int j = 0;
    int m = 0;
    
            string key = argv[1];
            int keylength = strlen(key);
            
            if (argc == 2)
            {  
                    for (m= 0; m <  keylength; m++)
                {
                    if isalpha(key[m])
                    {
                        
                    }
                    else
                    {
                        printf("Rejected\n");
                        return 1;
                    }
                }
                
            //printf("Provide a word to vigenere encrypt with the codeword you provided\n");
            string message = GetString();
            int messagelength = strlen(message);
            //get amount to change by
            
            //if keyword is alpha needs to be checked too as well as reject more than one arg. so if arc is 2 proceed else exit. and for checking the key word i dont know. i could do a quick for loop that runs first then runs to the next, and if at anypoint it is not alpha then return 1.


            for (i= 0, j= 0; i <  messagelength; i++)
            {
                if isalpha(message[i])
                {
                    if isupper(message[i])
                    {
                        if isupper(key[j %keylength])
                            {
                            //char a = message
                            //char b = 0
                            int encryptedchar = ((((message[i] + (key[j %keylength] - 65)) -65) %  26 ) +65);
                            j++;
                            printf("%c", encryptedchar);
                            }
                        if islower(key[j %keylength])
                            {
                            int encryptedchar = ((((message[i] + (key[j %keylength] - 97)) -65) %  26 ) +65);
                            j++;
                            printf("%c", encryptedchar);
                            }
                    }
                    
                    if islower(message[i])
                    {
                        if isupper(key[j %keylength])
                            {
                            int encryptedchar = ((((message[i] + (key[j %keylength] - 65)) -97) %  26 ) +97);
                            j++;
                            printf("%c", encryptedchar);
                            }
                        if islower(key[j %keylength])
                            {
                            int encryptedchar = ((((message[i] + (key[j %keylength] - 97)) -97) %  26 ) +97);
                            j++;
                            printf("%c", encryptedchar);
                            }
                    }
                        
                    }
                    
                   else
                            {
                                printf("%c", message[i]);
                            }  
                    
            } 
    
    printf("\n");
    
}
    else
    {
        printf("Rejected\n");
        return 1;
    }
}

//made by tyler loeper for CS50 2016