$($a$)$ Given the sequence $6,8,1,7,4,2,5,9,$ perform stack operations from left to right of push and pop

operations such that the pop operations would produce the output $6,7,4,1,9.$ Show the items still

in the stack. The stack object stk is created from the class Stack. You should show stack

configuration or container for each operation performed. For example, stk$.$push$(10)$ and stk$.$pop$()$

means push $10$ on stack and removed again.

$($b$)$ Given the sequence $6,4,2,5,9$ sort them into ascending order using the stack described in $($a$).$