Normal Stack

easy

1. You are required to complete the code of our CustomStack class. The class should mimic the behaviour of java.util.Stack class and implement LIFO semantic.
2. Here is the list of functions that you are supposed to complete
   2.1. push -&gt; Should accept new data if there is space available in the underlying 
   array or print "Stack overflow" otherwise.
   2.2. pop -&gt; Should remove and return last data if available or print "Stack 
   underflow" otherwise and return -1.
   2.3. top -&gt; Should return last data if available or print "Stack underflow" 
   otherwise and return -1.
   2.4. size -&gt; Should return the number of elements available in the stack.
   2.5. display -&gt; Should print the elements of stack in LIFO manner (space- 
   separated) ending with a line-break.
3. Input and Output is managed for you.

Input Format

Input is managed for you

Output Format

Output is managed for you

Constraints

None

Notice

Try First, Check Solution later

1. You should first read the question and watch the question video.
2. Think of a solution approach, then try and submit the question on editor tab.
3. We strongly advise you to watch the solution video for prescribed approach.

Example

Input

5
push 10
display
push 20
display
push 30
display
push 40
display
push 50
display
push 60
display
top
pop
display
top
pop
display
top
pop
display
top
pop
display
top
pop
display
top
pop
quit

Output

10 
20 10 
30 20 10 
40 30 20 10 
50 40 30 20 10 
Stack overflow
50 40 30 20 10 
50
50
40 30 20 10 
40
40
30 20 10 
30
30
20 10 
20
20
10 
10
10

Stack underflow
Stack underflow

Smallest Number Following Pattern

Dynamic Stack