Create StackUsingArray.java

[singhshreya-bhriguvanshi]

A program to implement a Stack using Array. Task is to use the class as shown in the comments in the code editor and complete the functions push() and pop() to implement a stack. The push() method takes one argument, an integer 'x' to be pushed into the stack and pop() which returns an integer present at the top and popped out from the stack. If the stack is empty then return -1 from the pop() method.

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