Pop Stack

Pop stack sends the data in the node at the top of the stack back to the calling algorithm. It then deletes and recycles the node ¾ that is, returns it to memory. After the count is adjusted by subtracting 1, the algorithm returns to the caller. If the pop was successful, it returns true; if the stack is empty when pop is called, it returns false.

algorithm popStack (ref stack ,

ref dataout )

This algorithm pops the item on the top of the stack and returns it to the user.

Pre stack is metadata structure to a valid stack

dataout is a reference variable to receive the data

post data have been returned to calling algorithm

Return true if successful; false if memory underflow

1 if (stack empty)

1 success = false

2 else

1 dltptr = Stack.top

2 dataout = stack.top->data

3 stack.top = stack.top->next

4 stack.count = stack.count – 1

5 recycle (dltptr)

6 success = true

3 end if

4 return success

end popStack