A stack is an abstract data type.The stack contains two main operations PUSH and POP. Push inserts an element to the top of the stack whereas pop eliminates the element that is on the top of the stack. This is depicted as LAST IN FIRST OUT. Yes, the last element that enters the stack by using push operation is the one which gets eliminated by the pop operation. This can be easily understood from the below Image. I have rote a fe line of cod in C to depict the above function.