stack.h

#include <stdio.h>
#define MAXSIZE 5

struct stack
{
				int stk[MAXSIZE];
				int top;
};
typedef struct stack STACK;
STACK s;

void push(void);
int  pop(void);
void displaystack(void);

void mainstack ()
{
				int choice;
				int option = 1;
				s.top = -1;

				printf ("STACK OPERATION\n");
				while (option)
				{
								printf ("\n");
								printf ("1-->PUSH\n");
								printf ("2-->POP\n");
								printf ("3-->DISPLAY\n");
								printf ("\n");

								printf ("Enter your choice\n");
								scanf    ("%d", &choice);
								switch (choice)
								{
												case 1:
																push();
																break;
												case 2:
																pop();
																break;
												case 3:
																displaystack();
																break;
												case 4:
																return;
								}

				}
}
void push ()
{
				int num;
				if (s.top == (MAXSIZE - 1))
				{
								printf ("Stack is Full\n");
								return;
				}
				else
				{
								printf ("Enter the element to be pushed\n");
								scanf ("%d", &num);
								s.top = s.top + 1;
								s.stk[s.top]=num;
				}
				return;
}
int pop ()
{
				int num;
				if (s.top == - 1)
				{
								printf ("Stack is Empty\n");
								return (s.top);
				}
				else
				{
								num = s.stk[s.top];
								printf ("poped element is = %d", s.stk[s.top]);
								s.top = s.top - 1;
				}
				return(num);
}
void displaystack ()
{
				int i;
				if (s.top == -1)
				{
								printf ("Stack is empty\n");
								return;
				}
				else
				{
								printf ("\n The status of the stack is \n");
								for (i = s.top; i >= 0; i--)
								{
												printf ("%d\n", s.stk[i]);
								}
				}
				printf ("\n");
}