Sorting and reversing a linked list

Program

# include <stdio.h>
# include <stdlib.h>
struct node
{
   int data;
   struct node *link;
};
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 reverse list */
struct node *reverse(struct node *p)
{
   struct node *prev, *curr;
   prev = NULL;
   curr = p;
   while (curr != NULL)
   {
      p = p-> link;
      curr-> link = prev;
      prev = curr;
      curr = p;
   }
   return(prev);
}
/* 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);
}

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 );
      start = reverse(start);
      printf("The reversed list is\n");
      printlist ( start );
}