Stack Push and Pop

Implement a stack of up to five integers using an array and a top pointer.

For each operation:

• P is followed by a value. Push it and output TRUE, or output FALSE if the stack is full.
• O pops and outputs the top value, or outputs -1 if the stack is empty.

Input: An operation count followed by operations and push values. Output: One result per operation.

Example:

Input:  4
        P 10
        P 20
        O
        O
Output: TRUE
        TRUE
        20
        10