Question

What is the top value and the size of a stack after doing the following operations?

push 500
push 430
top
pop
push 810
push 600
pop
a. size is two and the top value is 430
b. size is two and the top value is 810
c. size is three and the top value is 600
d. size is one and the top value is 600
e. size is one and the top value is 430

Answer 1

After performing the given sequence of stack operations, the size of the stack is two and the top value is 810, which corresponds to answer choice b.

We need to keep track of the operations performed on the stack to determine its final size and top value. The sequence of operations is as follows:

• push 500: Stack now has 1 item, top is 500.
• push 430: Stack now has 2 items, top is 430.
• top: Returns value at the top, which is 430, but doesn't remove it.
• pop: Removes the top item (430). Stack now has 1 item, top is 500.
• push 810: Stack now has 2 items, top is 810.
• push 600: Stack now has 3 items, top is 600.
• pop: Removes the top item (600). Stack now has 2 items, top is 810.

The final size of the stack is two and the top value is 810. Therefore, the correct answer is b. size is two and the top value is 810.