數據結構--多項式的加減運算

課程實驗，不足之處請指出

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
typedef struct Polynode
{
    int coef;
    int exp;
    struct Polynode *next;
}Polynode,*Polylist;
Polylist PolyCreate()
{
    Polynode *head,*rear,*s;
    int c,e;
    head=(Polynode*)malloc(sizeof(Polynode));
    rear=head;
    scanf("%d,%d",&c,&e);
    while(c!=0)
{
        s=(Polynode*)malloc(sizeof(Polynode));
        s->coef=c;
        s->exp=e;
        rear->next=s;
        rear=s;
        scanf("%d,%d",&c,&e);
}
    rear->next=NULL;
    return(head);
}
void PolyAdd(Polylist polya,Polylist polyb)
{
     Polynode *p,*q,*tail,*temp;
     int sum;
     p=polya->next;
     q=polyb->next;
     tail=polya;
     while(p!=NULL&&q!=NULL)
  {
      if(p->exp<q->exp)
   {
    tail->next=q;tail=p;p=p->next;
   }
         else if((p->exp)==(q->exp))
   {
             sum=p->coef+q->coef;
         if(sum!=0)
   {
             p->coef=sum;
             tail->next=p;
             tail=p;
             p=p->next;
             temp=q;
             q=q->next;
             free(temp);
   }
         else
   {
             temp=p;p=p->next;free(temp);
             temp=q;q=q->next;free(temp);
   }
   }
   else
   {
    tail->next=q;tail=q;q=q->next;}
  }
  if(p!=NULL)
   tail->next=p;
  else
   tail->next=q;
}
void Subtract(Polylist polya,Polylist polyb)
{
Polynode *p,*q,*tail,*temp;
int sum;
p=polya->next;
q=polyb->next;
tail=polya;
while(p!=NULL&&q!=NULL)
{
  if(p->exp<q->exp)
  {
   tail->next=p; tail=p; p=p->next;
  }
   else if(p->exp==q->exp)
   {
    sum=p->coef-q->coef;
    if(sum!=0)
    {
     p->coef=sum;
     tail->next=p;
                    tail=p;
     p=p->next;
     temp=q;q=q->next; free(temp);
    }
    else
    {
     temp=p; p=p->next; free(temp);
     temp=q; q=q->next; free(temp);
    }

   }

   else
   {
    tail->next=q; tail=q;
    q=q->next;
   }
}
   if(p!=NULL)
    tail->next=p;
   else
    tail->next=q;
}
void Print(Polylist v) 
{
Polylist s=v->next;
    int i=0;
    if(s)
  printf("f(x)=");
    else
  printf("f(x)=0\n");
while(s)
{   i=0;
        printf("%d",s->coef);
        while(i<abs(s->exp))
  {
   if(!(s->exp));
      else    
    s->exp>0?printf("*x"):printf("/x");
      i++;
  }
  if(s->next&&s->next->coef>=0)
   printf("+");
  s=s->next;
}
  putchar(’\n’);
}
int main()
{
Polylist p,q;
int flag=1;
char c;
while(flag)
{
  printf("1.create polylist\n");
  printf("2.add\n");
  printf("3.substract\n");
  printf("p.print polylist\n");
  printf("q.quit\n");
  c=getchar();
  switch(c)
  {
  case’1’:{printf("Creating the list.1 please input number:(for example (1,2))\n");
   p=PolyCreate();
   Print(p);
   printf("Creating the list.2 please input number:(for example (1,2))\n");
      q=PolyCreate();
   Print(q);break;}
  case’2’:printf("adding\n");
   PolyAdd(p,q);break;
  case’3’:printf("subtracting\n");
   Subtract(p,q);break;
  case’p’:printf("the result is : ");
   Print(p);
  case’q’:flag=0;
  }
}

return 0;
}