For example i have a stack of chars and i want to pop a word from the stack how do i know whem the word starts and ends inside a stack?
I have a program who separates words and i want to eliminate the word from the stack thats repeated so thats why im asking this question :)

start with strlen(name)-1 then pop untill limit is reached or when char itself ur popping got space in it

that is if the name itself is ended with null terminator

yes each word ends with the null terminator but how i search for a word in the stack?

you can just use strstr but if you want to do it with pop only you can start at end of the stack then keep popping till a space is reached when a space is reached u end that word and compare it with the specified word you want