stack_using_structure

#include <stdio.h>
#include <stdlib.h>
#define max_size 10
int n;
struct Stack
{
    int array[max_size];
    int top;
}stk;

void initialiser(int n)
{
    stk.top = -1;
}

int overflow()
{
    if(stk.top >= n-1)
    {
        return(1);
    }
    return(0);

}
int underflow()
{
    if(stk.top < 0)
    {
        return(1);
    }
    return(0);
}

void push(int value)
{
    if(overflow())
    {
        printf("\nCaution! Stack Overflow Condition!!!\n");
    }
    else
    {
        stk.array[++(stk.top)] = value;
        printf("\n");
    }
}

int pop()
{
    if(underflow())
    {
        printf("\nCaution! Stack Underflow Condition!!!\n");
    }
    else
    {
            return(stk.array[(stk.top)--]);
            printf("\n");
    }
}

int peek()
{
    if(underflow())
    {
        printf("\nCaution! Stack Underflow Condition!!!\n");
    }
    else
    {
        return(stk.array[stk.top]);
    }
}

void display()
{
    if(underflow())
    {
        printf("\nStack is Empty!!!\n");
    }
    else
    {
        printf("\nItems in the stack are:\n");
        for(int i = stk.top; i >= 0; i--)
        {
            printf("%d ",stk.array[i]);
        }
        printf("\n");
    }
}
void main()
{
    int user_input,push_ele;
    printf("\nEnter the Stack size: ");
    scanf("%d",&n);
    initialiser(n);

    start:
    printf("\nSelect any of the following options:\n");
    printf("PUSH - 1\nPOP - 2\nPEEK - 3\nDISPLAY - 4\nEXIT CODE - 5\n");
    scanf("%d",&user_input);

    switch (user_input)
    {
    case 1:
        printf("\nEnter the element to be Pushed inside the Stack: ");
        scanf("%d",&push_ele);
        push(push_ele);
        goto start;
        break;
    case 2:
        printf("\nPoped element from the Stack: %d",pop());
        printf("\n");
        goto start;
        break;
    case 3:
        printf("\nElement on the Top of the Stack: %d",peek());
        printf("\n");
        goto start;
        break;
    case 4:
        display();
        goto start;
        break;
    case 5:
        break;
    default:
        printf("\nPlease Select A Valid Option!!!");
        goto start;
        break;
    }
}