一元多项式的加法C++

#include<iostream.h>
#include<stdlib.h>
typedef struct term{
 int z;   //指数
 float x;     //系数
 struct term *next;
}term;
struct term *creatlink();    //创建多项式
int cmp(int  a,int b);    //指数比较
struct term * addin(struct term *a,struct term *b);   //加法运算
void list(struct term *a);

void main(){
struct term *A=creatlink();
list(A);
struct term *B=creatlink();
list(B);
struct term * C=addin(A,B);
cout<<endl<<"加法运算后："<<endl;
list(C);

}
void list(struct term *a){
struct term *aa;
aa=a->next;
while(aa){
cout<<aa->x<<"X"<<aa->z;
if(aa->next!=0)
cout<<"+";
aa=aa->next;
}
}
struct term * addin(struct term *a,struct term *b){        //加法
struct term *ahead;
struct term *bhead;
struct term *aa;
struct term *bb;
ahead=a; bhead=b;
aa=ahead->next;  bb=bhead->next;
while(aa&&bb){
int result=cmp(aa->z,bb->z);
switch(result){
case 2:ahead=aa;aa=aa->next;break;   //指数小
case 1: bhead->next=bb->next;ahead->next=bb;bb->next=aa;ahead=ahead->next;bb=bhead->next;break;
case 0: aa->x+=bb->x;
 if(aa->x!=0)
 {ahead=aa;}
 else
 {ahead->next=aa->next;free(aa);}
 bhead->next=bb->next;free(bb);bb=bhead->next;aa=ahead->next;break;
}
}
if(bb)
{while(bb)
{bhead->next=bb->next;ahead->next=bb;ahead=bb;bb=bhead->next;}
free(bhead);}
if(aa)
{while(aa)
{ahead=aa;aa=aa->next;}
}
ahead->next=NULL;
return a;

}
int cmp(int a,int b){
if(a==b)
return 0;
if(a>b)
return 1;
else 
return 2;
}

struct term *creatlink(){              //创建多项式
struct term *p;
struct term *head;
struct term *q;
p=(struct term *)malloc(sizeof(struct term));
p->z=-1;
p->x=0;
p->next=NULL;
head=p;
cout<<endl<<"请输入多项式的项数："<<endl;
int number0;
cin>>number0;
for(int i=1;i<=number0;i++){
q=(struct term *)malloc(sizeof(struct term));
cout<<"请输入第"<<i<<"项的系数和指数:"<<endl;
int n;
float m;
cin>>m>>n;
q->x=m;
q->z=n;
p->next=q;
p=q;
}
p->next=NULL;
return head;
}