While we wait for an answer to the question laserlight asked, I would like to point out one thing.
Putting the alphabet in double quotes makes it a string constant - meaning that the compiler will automatically append the string with a null character (\0). Therefore, the array size would need to be the number of characters in the string plus one for the null character.
Code:
char alphabet[27] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
You could get away with using 26 if you didn't want a string, but simply an array of chars. In that case, you would have to define each array element independently; something like:
Code:
char alphabet[26] = {'A','B','C', ... 'Z'};
/* just an example; each element would have to be assigned, I only used the
ellipsis because I didn't feel like typing out each letter */