void  polyadd(Polylist polya, Polylist polyb)
/*此函數(shù)用于將兩個(gè)多項(xiàng)式相加，然后將和多項(xiàng)式存放在多項(xiàng)式polya中，并將多項(xiàng)式ployb刪除*/
{
	Polynode  *p, *q, *pre, *temp;
	int sum;
	p=polya->next;   /*令 p和q分別指向polya和polyb多項(xiàng)式鏈表中的第一個(gè)結(jié)點(diǎn)*/
	q=polyb->next;        
	pre=polya;  /* r指向和多項(xiàng)式的尾結(jié)點(diǎn)*/
	while (p!=NULL && q!=NULL) /*當(dāng)兩個(gè)多項(xiàng)式均未掃描結(jié)束時(shí)*/
	{ 
		if  (p->exp < q->exp)
			/*如果p指向的多項(xiàng)式項(xiàng)的指數(shù)小于q的指數(shù)，將p結(jié)點(diǎn)加入到和多項(xiàng)式中*/
		{ 
			pre->next=p;  
			pre=p; 
			p=p->next;
		}
		else
			if ( p->exp == q->exp)  /*若指數(shù)相等，則相應(yīng)的系數(shù)相加*/
			{  
				sum=p->coef + q->coef;
				if (sum != 0)
				{ 
					p->coef=sum;
					pre->next=p; 
					pre=p;
					p=p->next;
					temp=q; 
					q=q->next; 
					free(temp);
				}
				else
				{  
					temp=p;
					p=p->next;
					free(temp); 
		/*若系數(shù)和為零，則刪除結(jié)點(diǎn)p與q，并將指針指向下一個(gè)結(jié)點(diǎn)*/
					temp=q; 
					q=q->next;
					free(temp);
				}
			}
			else
			{  
				pre->next=q;
				pre=q; /*將q結(jié)點(diǎn)加入到和多項(xiàng)式中*/
				q = q->next; 
			}
	}
	if(p!=NULL)  /*多項(xiàng)式A中還有剩余，則將剩余的結(jié)點(diǎn)加入到和多項(xiàng)式中*/
		pre->next=p;
	else      /*否則，將B中的結(jié)點(diǎn)加入到和多項(xiàng)式中*/
		pre->next=q;
}