C语言：用链表实现一元多项式的加法

/*
	一元多多项式的加法
	1.先创建链表，存储多项式
	2.输出多项式
	3.两个多项式相加
	4.输出多项式
*/

# include 
# include 

typedef struct dxs  //多项式节点
{
	float coe;  //系数
	int exp;   //指数
	struct dxs * pNext;  //指针域

}DXS, * PDXS;

PDXS creat_dxs();   //创建多项式
void traverse(PDXS pHead);   //遍历多项式链表
PDXS add(PDXS Da, PDXS Db);  //多项式求和

int main(void)
{
	//用链表结构，创建两个多项式
	PDXS Da = creat_dxs();
    traverse(Da);

	PDXS Db = creat_dxs();
    traverse(Db);

	//求两个多项式的加法
	PDXS Dj = add(Da, Db);
	traverse(Dj);

	return 0;
}

PDXS creat_dxs()
{
	PDXS pHead = (PDXS)malloc(sizeof(DXS)); //创建头结点
	pHead->pNext = NULL;  //尾指针

	PDXS pTail = pHead;
	PDXS pNew = NULL;

	int len;
	float c;
	int e;
	int i;

	printf("输入多项式的项数：len = ");
	scanf("%d", &len);

	for(i = 0; i < len; i++)
	{
		printf("分别输入第%d项的系数c、指数e:", i+1);
		scanf("%f%d", &c, &e);
		
		pNew = (PDXS)malloc(sizeof(DXS));

		//多项式项，系数、指数
		pNew->coe = c;
		pNew->exp = e;
		pNew->pNext = NULL;

		pTail->pNext = pNew;
		pTail = pNew;
	}

	return pHead;
}

//遍历链表
void traverse(PDXS pHead)
{
	PDXS p = pHead->pNext;  //首节点

	while(p != NULL)
	{
		printf("(%.2f %d), ", p->coe, p->exp);
		p = p->pNext;
	}
	printf("\n");
}


//多项式相加
PDXS add(PDXS Da, PDXS Db)
{
	PDXS Dj = (PDXS)malloc(sizeof(DXS));  //和的头结点
	Dj->pNext = NULL;
	PDXS pTail = Dj;  //和的尾节点

	PDXS Dah = Da->pNext;  //指向多项式的首节点
	PDXS Dbh = Db->pNext;

	//循环遍历多项式A，B
	while(Dah && Dbh)
	{
		//比较当前两节点的指数
		//当前 A项节点指数 < B项节点指数
		if(Dah->exp < Dbh->exp)
		{
			pTail->pNext = Dah;  //将此A项加入和链表中
			pTail = Dah;

			Dah = Dah->pNext;  //A多项式向后遍历
		}

		//当前 A项节点指数 < B项节点指数
		else if(Dah->exp > Dbh->exp)
		{
			pTail->pNext = Dbh;  //将此B项加入和链表中
			pTail = Dbh;

			Dbh = Dbh->pNext;  // //B多项式向后遍历
		}

		//如果两节点的指数相等
		else
		{
			//当前指数的系数和不为0
			//A项中保存系数和，把此A项加入和链表中
			if(0 != (Dah->coe + Dbh->coe))
			{
				Dah->coe = Dah->coe + Dbh->coe;
				pTail->pNext = Dah;
				pTail = Dah;		
			}
		
			//A,B都向后遍历
			Dah = Dah->pNext;
			Dbh = Dbh->pNext;			
		}
	}

	//插入剩余段
	if(Dah != NULL)
	{
		pTail->pNext = Dah;
	}
	if(Dbh != NULL)
	{
		pTail->pNext = Dbh;
	}

	return Dj;
}