singly data

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

typedef struct data
{
    int a;
    struct data *next;
}data;

data *head=NULL;

void insert_at_first(int x)
{
    data *newnode = (*data)malloc(sizeof(data));
    newnode ->a = x;
    newnode ->next = NULL;
    if(head==NULL)
    {
        head=newnode;
        return;
    }
    newnode -> next = head;
    newnode = head;
}

void insert_at_end(int x)
{
    data *node = (*data)malloc(sizeof(data));
    node -> a = x;
    node -> next = NULL;
    data *temp = head;
    if(head==NULL)
        {
            head = node;
            return;
        }
        while(temp -> next!=NULL)
        {
            temp = temp->next;
        }
        temp -> next = node;
}

void insert_at_ntn(int n, int x)
{
    data *new = (*data)malloc(sizeof(data));
    new -> a= x;
    new -> next = NULL;
    data *temp = head;
    if(head==NULL || n==1)
    {
        new -> next =head;
        head = new;
        return;
    }
   n = n-2;
   while(n-- && temp -> next != NULL)
   {
       temp = temp -> next;
   }
   new -> next = temp ->next;
   temp -> next = new;
}

void delete_by_pos(int n)
{
    data *temp = head;
    if(head==NULL)
    {
        printf("not found\n");
        return;
    }
    if(n==1)
    {
       head = temp -> next;
       free (temp);
       return;
    }
    n=n-2;
    while(n-- && temp ->next!=NULL)
    {
        temp = temp -> next;
    }
    data *del = temp -> next;
    if(del==NULL)
    {
        return;
    }
    temp -> next = del -> next;
    free (del);
}

void delete_by_value(int n)
{
    data *temp = head;
    if(temp ->a==n)
    {
        head = temp -> next;
        free (temp);
    }
    while(temp -> next != NULL)
    {
        if(temp ->next ->a==n)
        {
            data *del = temp ->next;
            temp ->next = temp ->next ->next;
            free (del);

        }
        temp = temp ->next;
    }
}

void search(int x)
{
    data *temp = head;
    int c=1;
    while(temp!=NULL)
    {
        if(temp ->a ==x)
        {
            printf("%d Found!\n",x);
            return;
        }
        else
        {
           c++;
           temp = temp -> next;
        }
    }
    if(c>1)
    {
        printf("%d not found\n",x);
        return;
    }
}

int count()
{
    int count = 0;
    data *temp = head;
    while(temp!=NULL)
    {
        count ++;
        temp = temp -> next;
    }
    printf("total element no: %d\n",count);
    return count;
}

int sum()
{
    int add = 0;
    data *temp = head;
     while(temp!=NULL)
    {

        add=add+temp->a;
        temp=temp->next;
    }
    printf("Sum of our total element: %5d\n",add);
    return add;
}

void avg(float a, float b)
{
    float avg;
    avg = a/b;
    printf("Avg: %.2f\n",avg);
}
void print()
{
     data *temp = head;
     while(temp!=NULL)
    {
        printf("%5d",temp->a);
        temp=temp->next;
    }
    printf("\n");
}

int main()

{
    int a1,a2,a3,a4,a5,a6,a7,a8,a9,a10;
    float c,s;
    printf("insert any data at first : ");
    scanf("%d", &a1);
    insert_at_first(a1);
    print();

    printf("Insert any data at first: ");
    scanf("%d",&a2);
    insert_at_first(a2);
    print();

    printf("Insert any data at first: ");

    printf("Insert any data at end: ");
    scanf("%d",&a4);
    insert_at_first(a4);
    print();

     printf("Insert any data at end: ");
    scanf("%d",&a5);
    insert_at_first(a5);
    print();

     printf("Insert any data at nth_position: ");
    scanf("%d",&a6);
    insert_at_first(a6);
    print();

     printf("Insert any data at nth_position: ");
    scanf("%d",&a7);
    insert_at_first(a7);
    print();

     printf("Insert any data at nth_position: ");
    scanf("%d",&a8);
    insert_at_first(a8);
    print();

     printf("Enter any value which you want to delete: ");
    scanf("%d",&a9);
    insert_at_first(a9);
    print();

     printf("Which value you want to search!: ");
    scanf("%d",&a10);
    search(a10);
     print();

      c=count();
    s=sum();
    avg(s,c);
}