A solution for Project Four

/* MCS 275 Project Four: Sorting Monomials */

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

typedef struct poly POLY;
struct poly
{
   float  coefficient;
   int    degree;
   POLY   *tail;
};

POLY *read ();
/* reads a list of monomials given by the user */

void print ( POLY *p );
/* prints the monomials on screen */

POLY *smallest ( POLY *p, int sd );
/* returns the monomial in p of smallest degree strictly larger than sd */

POLY *sort ( POLY *p );
/* sorts the monomials in decreasing degrees */ 

int main()
{
   POLY *p;

   printf("Reading a list of monomials.\n");
   p = read();
   printf("The list of monomials : \n");
   print(p);
   p = sort(p);
   printf("The sorted list of monomials : \n");
   print(p);

   return 0;
}

POLY* read ()
{
   POLY *p;
   float cff;
   int deg;
   
   p = NULL;
   printf("Give coefficient (0.0 to stop) : ");
   scanf("%f", &cff);
   if (cff != 0.0)
   {
      printf("Give the degree of the monomial : ");
      scanf("%d", °);
      p = (POLY*)calloc(1,sizeof(POLY));
      p->coefficient = cff;
      p->degree = deg;
      p->tail = read();
   }
   return p;
}

void print ( POLY *p )
{
   if (p != NULL)
   {
      printf("%f*x^%d\n", p->coefficient, p->degree);
      print(p->tail);
   }
}

POLY *smallest ( POLY *p, int sd )
{
   POLY *ptr,*minmon;
   int min = sd;

   minmon = NULL;
   for (ptr = p; ptr != NULL; ptr = ptr->tail)
   {
      if (ptr->degree > sd)
      {
         if (min == sd)
         {
            min = ptr->degree;
            minmon = ptr;
         }
         else if (ptr->degree < min)
         {
            min = ptr->degree;
            minmon = ptr;
         }
      } 
   }
   return minmon;
}

POLY *sort ( POLY *p )
{
   POLY *sp;
   int smalldeg = -1;
   POLY *smallmon,*newmon;

   if (p == NULL)
      sp = NULL;
   else if (p->tail == NULL)
      sp = p;
   else
   {
      sp = NULL;
      smallmon = smallest(p,smalldeg);
      while (smallmon != NULL)
      {
         newmon = (POLY*)calloc(1,sizeof(POLY));
         newmon->coefficient = smallmon->coefficient;
         newmon->degree = smallmon->degree;
         newmon->tail = sp;
         sp = newmon;
         smallmon = smallest(p,smallmon->degree);
      }
   }
   
   return sp;
}