Inserting a new node in a sorted list

Program

Here is a complete program to insert an element in a sorted list of elements using the linked list representation so that after insertion, it will remain a sorted list.

# include <stdio.h>
# include <stdlib.h>
struct node
{
int data;
struct node *link;
};
struct node *insert(struct node *, int);
struct node *sinsert(struct node*, int );
void printlist ( struct node * );
struct node *sortlist(struct node *);

struct node *insert(struct node *p, int n)
{
   struct node *temp;
   if(p==NULL)
   {
      p=(struct node *)malloc(sizeof(struct node));
      if(p==NULL)
      {
   printf("Error\n");
           exit(0);
      }
      p-> data = n;
      p-> link = NULL;
   }
   else
   {
      temp = p;
      while (temp-> link!= NULL)
     temp = temp-> link;
      temp-> link = (struct node *)malloc(sizeof(struct node));
      if(temp -> link == NULL)
      {
   printf("Error\n");
          exit(0);
       }
     temp = temp-> link;
       temp-> data = n;
       temp-> link = NULL;
       }
      return (p);
}

void printlist ( struct node *p )
{
      printf("The data values in the list are\n");
      while (p!= NULL)
      {
   printf("%d\t",p-> data);
         p = p-> link;
      }
   }

/* a function to sort a list */
struct node *sortlist(struct node *p)
{
   struct node *temp1,*temp2,*min,*prev,*q;
   q = NULL;
   while(p != NULL)
   {
   prev = NULL;
      min = temp1 = p;
      temp2 = p -> link;
      while ( temp2 != NULL )
      {
         if(min -> data > temp2 -> data)
              {
         min = temp2;
                 prev = temp1;
               }
               temp1 = temp2;
               temp2 = temp2-> link;
            }
      if(prev == NULL)
            p = min -> link;
            else
            prev -> link = min -> link;
            min -> link = NULL;
            if( q == NULL)
            q = min; /* moves the node with lowest data value in the list
pointed to by p to the list
   pointed to by q as a first node*/
            else
            {
               temp1 = q;
               /* traverses the list pointed to by q to get pointer to its
last node */
               while( temp1 -> link != NULL)
               temp1 = temp1 -> link;
               temp1 -> link = min; /* moves the node with lowest data value
in the list pointed to
   by p to the list pointed to by q at the end of list pointed by
   q*/
         }
      }
      return (q);
   }

   /* a function to insert a node with data value n in a sorted list
pointed to by p*/
   struct node *sinsert(struct node *p, int n)
   {
      struct node *curr, *prev;
      curr =p;
      prev = NULL;
     while(curr ->data < n)
           {
                        prev = curr;
                  curr = curr->link;
           }
   if ( prev == NULL) /* the element is to be inserted at the start of
the list because
                   it is less than the data value of the first node*/
       {
            curr = (struct node *) malloc(sizeof(struct node));
            if( curr == NULL)
              {
                printf("error cannot allocate\n");
                exit(0);
              }
           curr->data = n;
           curr->link = p;
           p = curr;
       }
       else
        {
            curr->data = n;
            curr->link = prev->link;
            prev->link = curr;
        }
      return(p);
      }

      void main()
      {
         int n;
         int x;
         struct node *start = NULL ;
         printf("Enter the nodes to be created \n");
         scanf("%d",&n);
         while ( n-- > 0 )
         {
      printf( "Enter the data values to be placed in a node\n");
            scanf("%d",&x);
            start = insert ( start,x);
         }
         printf("The created list is\n");
         printlist ( start );
         start = sortlist(start);
         printf("The sorted list is\n");
         printlist ( start );
         printf("Enter the value to be inserted\n");
         scanf("%d",&n);
         start = sinsert(start,n);
         printf("The list after insertion is\n");
         printlist ( start );
   }