how to store an alphabet from an array[26] to another array

[snehlta]

I have taken two arrays p[26]={'A','B'- - - 'Z'} and array s[m].I want that to select a desirable alphabet from p[26] array and to store it in s[m],and keep incrementing 'm' till I am able to display a string of desirable length.I dont know what length should I take of second array,s[m].I just want that the alphabets which I select from p[26] should be stored in s[m],next alphabet again in s[m] and side wise incrementing the value of m.