linked list in c

#include<stdio.h>
#include<stdlib.h>
void insertAtBeginning(int);
void insertAtEnd(int);
void insertBetween(int,int,int);
void display();
void removeBeginning();
void removeEnd();
void removenode(int);
struct Node
{
   int data;
   struct Node *next;
}*head = NULL;
int main()
{
   int opt,value,opt1,val1,val2;
 while(1)
 {
   mainmenu : printf("\n\n MENU \n1. Insert\n2. Display\n3. Delete\n4. Exit\nEnter your choice: ");
   scanf("%d",&opt);
   switch(opt)
   {
      case 1:   printf("Enter the value to be insert: ");
                scanf("%d",&value);
        while(1)
        {
                printf("Where you want to insert: \n1. At Beginning\n2. At End\n3. Between\nEnter your choice: ");
                scanf("%d",&opt1);
                switch(opt1)
                {
                   case 1: insertAtBeginning(value);
                                   break; 
                   case 2: insertAtEnd(value);
                                   break;
                   case 3: printf("Enter the two values where you want to insert: ");
                                   scanf("%d%d",&val1,&val2);
                                   insertBetween(value,val1,val2);
                                break;
                                
                  /* default:   printf("\nWrong InputTry again");*/
                }
        goto mainmenu;
        }
        break;
                
      case 2:   display();
                break;
      case 3:   printf("How do you want to Delete: \n1. From Beginning\n2. From End\n3. given_node\nEnter your choice: ");
                scanf("%d",&opt1);
                switch(opt1)
                {
                   case 1:      removeBeginning();
                                break;
                   case 2:      removeEnd(value);
                                break;
                   case 3:      printf("Enter the value which you want to delete: ");
                                scanf("%d",&val2);
                                removenode(val2);
                                break;
                   default:     printf("\nWrong Input!! Try again!!!\n\n");
                                goto mainmenu;
                }
                break;
      case 4:   exit(0);
      default: printf("\nWrong input!!! Try again!!\n\n");
   }
   }
}

void insertAtBeginning(int value)
{
   struct Node *newNode;
   newNode = (struct Node*)malloc(sizeof(struct Node));
   newNode->data = value;
   if(head == NULL)
   {
      newNode->next = NULL;
      head = newNode;
   }
   else
   {
      newNode->next = head;
      head = newNode;
   }
   printf("\nOne node inserted!!!\n");
}
void insertAtEnd(int value)
{
   struct Node *newNode;
   newNode = (struct Node*)malloc(sizeof(struct Node));
   newNode->data = value;
   newNode->next = NULL;
   if(head == NULL)
        head = newNode;
   else
   {
      struct Node *temp = head;
      while(temp->next != NULL)
        temp = temp->next;
      temp->next = newNode;
   }
   printf("\nOne node inserted!!!\n");
}
void insertBetween(int value, int loc1, int loc2)
{
   struct Node *newNode;
   newNode = (struct Node*)malloc(sizeof(struct Node));
   newNode->data = value;
   if(head == NULL)
   {
      newNode->next = NULL;
      head = newNode;
   }
   else
   {
      struct Node *temp = head;
      while(temp->data != loc1 && temp->data != loc2)
        temp = temp->next;
      newNode->next = temp->next;
      temp->next = newNode;
   }
   printf("\nOne node inserted!!!\n");
}

void removeBeginning()
{
   if(head == NULL)
        printf("\n\nList is Empty!!!");
   else
   {
      struct Node *temp = head;
      if(head->next == NULL)
      {
         head = NULL;
         free(temp);
      }
      else
      {
        head = temp->next;
        free(temp);
        printf("\nOne node deleted!!!\n\n");
      }
   }
}
void removeEnd()
{
   if(head == NULL)
   {
      printf("\nList is Empty!!!\n");
   }
   else
   {
      struct Node *temp1 = head,*temp2;
      if(head->next == NULL)
        head = NULL;
      else
      {
         while(temp1->next != NULL)
         {
            temp2 = temp1;
            temp1 = temp1->next;
         }
         temp2->next = NULL;
      }
      free(temp1);
      printf("\nOne node deleted!!!\n\n");
   }
}
void removenode(int delValue)
{
   struct Node *temp1 = head, *temp2;
   while(temp1->data != delValue)
   {
     if(temp1 -> next == NULL){
        printf("\nGiven node not found in the list!!!");
     }
     temp2 = temp1;
     temp1 = temp1 -> next;
   }
   temp2 -> next = temp1 -> next;
   free(temp1);
   printf("\nOne node deleted!!!\n\n");
 }
void display()
{
   if(head == NULL)
   {
      printf("\nList is Empty\n");
   }
   else
   {
      struct Node *temp = head;
      printf("\n\nList elements are - \n");
      while(temp->next != NULL)
      {
         printf("%d --->",temp->data);
         temp = temp->next;
      }
      printf("%d --->NULL",temp->data);
   }
}

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

int main()
{
  //node structure
  struct node
  {
      int data;
      struct node *next;
  };

  //declaring nodes
  struct node *head,*middle,*last;

  //allocating memory for each node
  head   = malloc(sizeof(struct node));
  middle = malloc(sizeof(struct node));
  last   = malloc(sizeof(struct node));

  //assigning values to each node
  head->data   = 10;
  middle->data = 20;
  last->data   = 30;

  //connecting each nodes. head->middle->last
  head->next   = middle;
  middle->next = last;
  last->next   = NULL;

  //temp is a reference for head pointer.
  struct node *temp = head;

  //till the node becomes null, printing each nodes data
  while(temp != NULL)
  {
      printf("%d->",temp->data);
      temp = temp->next;
  }
  printf("NULL");

  return 0;
}