STACK Pop Quiz

What does LIFO stand for in the context of a stack?

• Last In, Last Out

• First In, First Out

• Last In, First Out

• First In, Last Out

What happens during a *stack underflow*?

• The stack is full

• An attempt is made to pop from an empty stack

• The stack contains invalid data

• The stack is corrupted

Which two structures are required to implement a linked list stack?

• Array and pointer

• Stack head (metadata) and data nodes

• Queue and linked list

• Stack and heap

How does a stack help in reversing data?

• By sorting elements in ascending order

• By pushing elements in and popping them in reverse order

• By randomly shuffling elements

• By deleting the middle element first

What is the postfix form of the infix expression `A + B * C`?

• `A B + C *`

• `A B C * +`

• `A B C + *`

• `A + B C *`

What is the result of evaluating the postfix expression `3 4 + 5 *`?

• 12

• 23

• 35

• 47

In the `pushStack` algorithm, which step ensures the new node becomes the top?

• `stack.count++`

• `newPtr->data = data`

• `stack.top = newPtr`

• `newPtr->next = stack.top`

Which real-world application uses stacks for navigation?

• Text editors (Undo/Redo)

• Web browsers (Back/Forward buttons)

• Spreadsheet calculations

• Database indexing

Which attribute in the stack head structure tracks the number of elements?

• `top`

• `count`

• `size`

• `capacity`

When does a stack enter an overflow state?

• When the stack is empty

• When there is no memory to push a new item

• When an invalid operation is performed

• When the stack is corrupted