What is stacking and push() and pop() functions ?? [In detail]

Question

in terms of pointers if possible !!

Answer 1

stack is a data structure which saves data in the form of FILO (first in last out)
the basic operations are push(val) and pop()
push(val) puts val at the top of the stack
pop() gets the last value that was pushed
lets see a pseudo code example (stack values are pushed from left to right, meaning most left is the top)

st = new stack()
st: (empty)
st.push(5)
st: |5|
st.push(8)
st: |8|5|
st.push(2)
st: |2|8|5|
x = st.pop()
x: 2
st: |8|5|
y = st.pop()
y: 8
st: |5|

as you can observe, the last value that can be popped is the one that was pushed first: 5, hence FILO
and that's the basic stuff of it

Answer 2

push() puts an element at the end of the stack