STACK_OPER

//siddhanta das
#include<stdio.h>
#include<stdlib.h>
#define MAX 5

int s[MAX];
int top = -1;

void push(int item);
int pop();
void palindrome();
void display();

void main()
{
            int choice, item;
            while(1)
            {
                        printf("\n\Menu : ");
                        printf("\n=>1.Push an Element to Stack and Overflow demo ");
                        printf("\n=>2.Pop an Element from Stack and Underflow demo");
                        printf("\n=>3.Palindrome demo ");
                        printf("\n=>4.Display ");
                        printf("\n=>5.Exit");
                        printf("\nEnter your choice: ");
                        scanf("%d", &choice);
                        switch(choice)
                        {
                                    case 1:             printf("\nEnter an element to be pushed: ");
                                                            scanf("%d", &item);
                                                            push(item);
                                                            break;
                                    case 2:             item = pop();
                                                            if(item != -1)
                                                                        printf("\nElement popped is: %d", item);
                                                            break;
                                    case 3:             palindrome();
                                                            break;
                                    case 4:             display();
                                                            break;
                                    case 5:             exit(1);
                                    default:            printf("\nPlease enter valid choice ") ;
                                                            break;
                    }
            }
}

void push(int item)
{
            if(top == MAX-1)
            {
                        printf("\nStack overflow");
                        return;
            }

            top = top + 1 ;
            s[top] = item;
}

int pop()
{
            int item;
            if(top == -1)
            {
                        printf("\n~~~~Stack underflow~~~~");
                        return -1;
            }
            item = s[top];
            top = top - 1;
            return item;
}

void display()
{
            int i;
            if(top == -1)
            {
                        printf("\n~~~~Stack is empty~~~~");
                        return;
            }
            printf("\nStack elements are:\n ");
            for(i=top; i>=0 ; i--)
                        printf("| %d |\n", s[i]);
}

void palindrome()
{
            int flag=1,i;
            printf("\nStack content are:\n");
            for(i=top; i>=0 ; i--)
                        printf("| %d |\n", s[i]);

            printf("\nReverse of stack content are:\n");
            for(i=0; i<=top; i++)
                        printf("| %d |\n", s[i]);

            for(i=0; i<=top/2; i++)
            {
                        if( s[i] != s[top-i] )
                        {
                                    flag = 0;
                                    break;
                        }
            }
            if(flag == 1)
            {
                        printf("\nIt is palindrome number");
            }
            else
            {
                        printf("\nIt is not a palindrome number");
            }
}