Consider these functions:

push$()$ : push an element into the stack

pop$()$ : pop the top$-$of$-$the$-$stack element

top$()$ : returns the item stored in top$-$of$-$the$-$stack$-$node

What will be the output after performing these sequence of operations

push $(20)$; push $(4)$; top$()$; pop$()$;pop$()$; push$(5)$; top$()$;

Your answer:

$20$

stack underflow

$4$

no output

error

$5$

Clear answer