cs50 2016

week4
NodeList

datastructure
stack
queue

compressor

hashing table

week2
initilaize
int main(int argc, string argv[])
$ ./initials ccc  => argc ==2;
$ ./initials ccc  => argv[1]==ccc;


//這個卡了我三個小時
if(s[i] == '\0')  <--一直想這樣弄結果卡在這
if(s[i] == ' ')
{
i++;
printf("%c", toupper(s[i]));
}

http://imil.au.edu.tw/~hsichcl/TurboC/C_Unit10.htm
http://programming.im.ncnu.edu.tw/Chapter10.htm

caesar 終於卡沒那麼那麼久了  放煙火
printf("%c\n", plaintext[i]); 

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

int main(int argc, string argv[])
{
    if (argc == 2)
    {
    string plaintext = get_string();
    int key = atoi(argv[1]);
    // printf("plaintext:");
    // printf("%s\n",plaintext);
        for(int i = 0, n = strlen(plaintext); i < n; i++)
        {
            if(isalpha(plaintext[i]))
            {  
                if(isupper(plaintext[i]))
                {
                    int upc = (plaintext[i] + key - 65) % 26 + 65;
                    printf("%c", upc);
                }else
                {
                    int lpc = (plaintext[i] + key - 97) % 26 + 97;
                    printf("%c", lpc);
                }
            }else{
                printf("%c", plaintext[i]);
            }
        }
    }
    printf("\n");
}