I use a string:
char word[100];
I add some chars to each position starting at 0. But then I need be able to clear all those positions so that I can start add new characters starting at 0.
If I don't do that then if the second string is shorten then the first one I end up having extra characters from the first string when adding the second one since I don't overwrite them.
If you want to zero out the whole array, you can:
memset(word, 0, sizeof(word));