Stack Pseudocode

Stacks can be implemented using an array data structure, with each element of the array representing an item in the stack. New items are placed on the stack using push and items are removed using pop. A variable ‘top’ holds the position of the topmost item in the stack, and size holds the maximum number of items the stack can hold.

S is the stack being operated on and x is the item to add to the stack.

        Push(S,x)
        IF top == size THEN
          Stack is full
        ELSE
        BEGIN
          top++
          S[top] = x
        END 

    Pop(S) 
    IF top == 0 THEN 
      Stack is empty 
    ELSE 
    BEGIN 
      x = S[top] 
      top-- 
      return x 
    END