Singly linked list

#include<stdio.h>
#include<stdlib.h>

int flag=1;

typedef struct Node
{
    int data;
    struct Node *next;
} node;


void insert(node *pointer, int data)
{
    while(pointer -> next != NULL)
    {
        pointer = pointer -> next;
    }

    pointer -> next = (node*)malloc(sizeof(node)); //Allocate memory for new node
    pointer = pointer -> next; //Move pointer to newly allocated node
    pointer -> data = data; //Set data field of new node
    pointer -> next = NULL; //Set next field of new node to NULL to indicate end of list

    printf("\n    Data successfully inserted...");
}


void delete(node *pointer, int data)
{
    while(pointer->next!=NULL && (pointer -> next) -> data!=data)
    {
        pointer = pointer -> next;
    }

    if(pointer -> next == NULL)
    {
        printf("\n    '%d' isn't present in the list!", data);
        return;
    }

    node *temp;
    temp = pointer->next;
    pointer->next = temp->next;

    free(temp);

    printf("\n    Data successfully deleted...");

}

void print(node *pointer)
{

    if(pointer == NULL && flag == 1)
    {
        printf("\n    The list is empty!");
    }

    if(pointer == NULL)
    {
        return;
    }

    else
    {
        flag = 0;
        printf("  %d", pointer -> data);
        print(pointer->next);
    }

    flag = 1;
}


int find(node *pointer, int data)
{
    pointer = pointer->next;

    while(pointer != NULL)
    {
        if(pointer->data == data)
        {
            return 1;
        }
        pointer = pointer->next;
    }

    return 0;
}


void update(node *pointer, int data)
{
    int new_data;
    printf("\n    Enter new data: ");
    scanf("%d", &new_data);

    pointer = pointer->next;

    while(pointer != NULL)
    {
        if(pointer->data == data)
        {
            pointer->data = new_data;
            printf("\n    Data update successful...");
        }

        pointer = pointer->next;
    }

    return;
}


int main(void)
{
    node *start, *temp;
    start = (node*)malloc(sizeof(node));
    temp = start;
    temp -> next = NULL;

    printf("1. Insert\n
            2. Delete\n
            3. Print\n
            4. Find\n
            5. Update\n
            6. Terminate this program");

    while(flag!=0)
    {
         int query;
         printf("\n\nEnter your choice : ");
         scanf("%d", &query);

         if(query == 1)
         {
             int data;
             printf("\n    Enter the data that you want to insert : ");
             scanf("%d", &data);

             insert(start, data);
         }

         else if(query == 2)
         {
             int data;
             printf("\n    Enter the data that you want to delete : ");
             scanf("%d", &data);

             delete(start, data);
         }

         else if(query == 3)
         {
             printf("\n    List:");
             print(start->next);
         }

         else if(query == 4)
         {
             int data;
             printf("\n    Enter the data that you want to find : ");
             scanf("%d", &data);

             int status = find(start, data);

             if(status == 1)
             {
                printf("\n    Found...");
             }
             else
             {
                printf("\n    Data is not in the list!");
             }
         }

         else if(query == 5)
         {
             int data;
             printf("\n    Enter the data that you want to update : ");
             scanf("%d", &data);

             int flag = find(start, data);

             if(flag == 1)
             {
                printf("\n    Found...");

                update(start, data);
             }
             else
             {
                printf("\n    Data is not in the list!");
             }
         }

         else if(query == 6) flag = 0;
    }

    printf("\n\nProgram terminated!\n\n");

    return 0;
}