One by one pop all characters from stack and put them back to string.

$3.$ Reverse a number using stack $-$ Given a number, write a program to reverse this number using stack.

Examples:

Input : $365$

Output : $563$

Input : $6899$

Output : $9986$

Notes on problem $3$

The idea to do this is to extract digits of the number and push the digits on to a stack. Once all of the digits of the number are pushed to the stack, we will start popping the contents of stack one by one and form a number.

As stack is a LIFO data structure, digits of the newly formed number will be in reverse order.