Simple Stack Implementation By Array

#include<stdio.h>
#include <stdbool.h>

void init_stack(int);
void push(int);
int pop();
int peek();
void print(int);

int top = -1;
int stack[];

int main()
{
    int item, stack_size;

    printf("Size of your stack : ");
    scanf("%d", &stack_size);
    printf("This Stack Allows Only Integer Value!");
    stack[stack_size];

    init_stack(stack_size); //initializing the stack array with zeros

    bool t = true;
    while(t)
    {
        printf("\n\n1. Push\n2. Pop\n3. Peek\n4. isEmpty\n5. isFull\n6. Print Stack\n7. Exit");
        printf("\n\nChoose : ");

        int c;
        scanf("%d", &c);

        switch(c)
        {
            case 1 :
                printf("\n\nitem : ");
                scanf("%d", &item);

                if(top < stack_size-1)
                {
                    push(item);
                    printf("\nSuccessful...");
                }
                else printf("\n\tStack overflow!");
                break;

            case 2 :
                if(top > -1)
                {
                    item = pop();
                    printf("\nPopped item is : %d", item);
                }
                else printf("\n\tStack underflow!");
                break;

            case 3 :
                if(top > -1)
                {
                    item = peek();
                    printf("\nTop item is : %d", item);
                }
                else printf("\nStack is empty!");
                break;

            case 4 :
                if(top > -1) printf("\nStack is not empty.");
                else printf("\nStack is empty!");
                break;

            case 5 :
                if(top < stack_size-1) printf("\nStack is not full.");
                else printf("\nStack is full!");
                break;

            case 6 :
                printf("\n\nCurrent stack :");
                print(stack_size);
                break;

            default :
                t = false;
        }
    }

    return 0;
}

void push(int item)
{
    top++;
    stack[top] = item;
}

int pop()
{
    int item = stack[top];
    stack[top] = 0;  //deleting the item from the stack
    top--;
    return item;
}

int peek()
{
    return stack[top];
}

void print(int n)
{
    for(int i=0; i<n; i++)
    {
        printf("\t%d", stack[i]);
    }
}

void init_stack(int n)
{
    for(int i=0; i<n; i++)
    {
        stack[i] = 0;
    }
}