C Program to implement basic operation of Stacks using global variables

Program

#include<stdio.h>
#include<stdlib.h>
#define STACK_SIZE 5
int top;
int s[STACK_SIZE];
int item;
void push()
{
	if(top == STACK_SIZE -1)
	{
		printf("Stack Overflow\n");
		return;
	}
	s[++top] = item;
}
int pop()
{
	int item_deleted;
	if(top == -1)
	{
		return 0;
	}
	item_deleted = s[top];
	top--;
	return item_deleted;
}
void display()
{
	int i;
	if(top == -1)
	{
		printf("Stack is empty\n");
		return;
	}
	printf("Contents of the stack are:\n");
	for(i = 0; i <= top; i++)
	{
		printf("%d\n",s[i]);
	}
}
void main()
{
	int item_deleted, choice;
	top = -1;
	for(;;)
	{
		printf("Enter the choice\n");
		printf("1: Push\n2: Pop\n3: Display\n4: Exit\n");
		scanf("%d",&choice);
		switch(choice)
		{
			case 1:
				printf("Enter the item to be inserted\n");
				scanf("%d",&item);
				push();
				break;
			case 2:
				item_deleted = pop();
				if(item_deleted == 0)                    
					printf("Stack is empty\n");
		                else
		                	printf("Item deleted = %d\n",item_deleted);
		                break;
			case 3:
				display();
				break;
			default:
				exit(0);
		}
	}
}

Output

Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
10
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
20
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
30
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
40
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
50
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
1
Enter the item to be inserted
60
Stack Overflow
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
3
Contents of the stack are:
10
20
30
40
50
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Item deleted = 50
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Item deleted = 40
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Item deleted = 30
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Item deleted = 20
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Item deleted = 10
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
2
Stack is empty
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
3
Stack is empty
Enter the choice
1: Push
2: Pop
3: Display
4: Exit
4