线性表---一元多项式相加

线性表链式存储实现一元多项式相加。

//Define.h内为基本定义

#include<stdio.h>

#include<Define.h>
#include<stdlib.h>

typedef int ElemType;

typedef struct LNode
{
	float coef;						//系数
	ElemType expn;						//指数
	struct LNode *next;
}LNode, *LinkList;

typedef struct
{
	float coef;						//系数
	ElemType expn;						//指数
}term;

typedef LinkList polynomail;		//有序链表表示多项式

Status InitPolyn(polynomail *P);					//初始化链表
Status MakeNode(polynomail *P, term e);				//开辟新的节点，用e赋值
void CreatPolyn(polynomail *P, int m);				//建立新的链表，输入m项的系数和指数
void DestroyPolyn(polynomail *P);					//销毁链表
Status PrintPolyn(polynomail P);					//打印输出链表
int PolynLength(polynomail P);						//得到链表的长度
Status SetCurElem(polynomail *P, term e);			//用e给链表P的节点赋值
Status LocateElem(polynomail P, term e, polynomail *q, Status (*compare)(term, term));			
int cmp (term a, term b);
Status InsFirst(polynomail *p, polynomail *s);       //插入
Status DelFirst(polynomail *p, polynomail *q);		//删除
void AddPolyn(polynomail *Pa, polynomail *Pb);		//多项式的加法, 并且销毁Pb

Status InitPolyn(polynomail *P)
{
	(*P) = (LinkList)malloc(sizeof(LNode));
	(*P)->next = NULL;
	if ((*P) == NULL)
	{
		return ERROR;
	}
	(*P)->coef = 0.0;
	(*P)->expn = -1;
	printf("初始化成功!\n");
	return OK;
}

Status SetCurElem(polynomail *P, term e)
{
	if ((*P) == NULL)
	{
		return ERROR;
	}
	(*P)->coef = e.coef;
	(*P)->expn = e.expn;
	return OK;
}
Status cmp(term a, term b)
{
	if (a.expn < b.expn)
	{
		return -1;
	}
	else if (a.expn == b.expn)
	{
		return 0;
	}
	else
	{
		return 1;
	}
}
Status LocateElem(polynomail P, term e, polynomail *q, Status (*compare)(term, term))  //小于
{
	polynomail p, prior;
	term x;
	for (p = P->next, prior = P; p != NULL; p = p->next, prior = prior->next)
	{
		x.coef = p->coef;
		x.expn = p->expn;
		if (cmp(x, e) == 0)
		{
			(*q) = p;
			return TRUE;
		}
		else if (cmp(x, e) == 1)
		{
			(*q) = prior;
			return FALSE;
		}
	}
	(*q) = prior;			//重要
	return FALSE;
}

Status MakeNode(polynomail *p, term e)
{
	(*p) = (polynomail)malloc(sizeof(LNode));
	(*p)->next = NULL;
	if ((*p) == NULL)
	{
		return ERROR;
	}
	else
	{
		(*p)->coef = e.coef;
		(*p)->expn = e.expn;
		return TRUE;
	}
}

Status InsFirst(polynomail *p, polynomail *s)
{
	(*s)->next = (*p)->next;
	(*p)->next = (*s);
	
	return OK;
}

Status DelFirst (polynomail *p, polynomail *q)	//删除
{
	(*p)->next = (*q)->next;
	(*q)->next = NULL;

	return OK;
}

void CreatPolyn(polynomail *P, int m)
{
	int i;
	polynomail head, q, s;
	term e;
	head = (*P);
	e.coef = 0.0;
	e.expn = -1;
	SetCurElem(&head, e);
	for (i = 1; i <=m; i ++)
	{
		scanf("%f%d", &e.coef, &e.expn);
		if (! LocateElem (*P, e, &q, (* cmp)))
		{
			if (MakeNode (&s, e))
			{
				InsFirst(&q, &s);
			}
		}
		else
		{
			q->coef += e.coef;						//优化
		}
	}
//	free(s);
}

void AddPolyn(polynomail *Pa, polynomail *Pb)
{
	float sum;
	term a, b;
	polynomail ha, hb, qa, qb;

	ha = (*Pa); hb = (*Pb);
	qa = ha->next;
	qb = hb->next;

	while (qa && qb)
	{
		a.coef = qa->coef;
		a.expn = qa->expn;
		b.coef = qb->coef;
		b.expn = qb->expn;
		switch (cmp (a, b))					//参数是term型
		{
		case -1:
			ha = qa;
			qa = qa->next;
			break;
		case 0:
			sum = a.coef + b.coef;
			if (sum != 0)
			{
				qa->coef = sum;
				ha = qa;
			}
			else
/*			{
				DelFirst (&hb, &qb);
				free(qb);

				qb = hb ->next;
				qa = ha->next;
				break;
			}*/
			{
				DelFirst(&ha, &qa);
				free(qa);
			}
			DelFirst(&hb, &qb);
			free(qb);
			qb = hb->next;
			qa = ha->next;
			break;
		case 1:
			DelFirst(&ha, &qb);
			InsFirst(&ha, &qb);
			qb = hb->next;
			ha = ha->next;
			break;
		}
	}
	if ((*Pb) != NULL)
	{
//		qa->next = qb;
		ha->next = qb;
	}
	free(hb);
}

Status PrintPolyn(polynomail P)						//打印输出链表
{
	polynomail p;
	p = P->next;
	if (p == NULL)
	{
		printf("F(x) = 0\n");
		return 0;
	}
	printf("F(x) = ");
	while(p)
	{
//		if (p->next == NULL)
		if (p == P->next)
		{
			if (p->coef < 0 && p->coef == -1)
			{
				printf("-x^(%d)", p->expn);
			}
			else if (p->coef < 0 && p->coef != -1)
			{
				printf("%.1fx^(%d)", p->coef, p->expn);
			}
			else if (p->coef == 1)
			{
				printf("x^(%d)", p->expn);
			}
			else if (p->expn == 1)
			{
				printf("%.1fx", p->coef);
			}
			else if (p->expn == 0)
			{
				printf("%.1f", p->coef);
			}
			else
			{
				printf("%.1fx^(%d)", p->coef, p->expn);
			}	
		}
		else
		{	
			if (p->coef < 0 && p->coef == -1)
			{
				printf("-x^(%d)", p->expn);
			}
			else if (p->coef < 0 && p->coef != -1)
			{
				printf("%.1fx^(%d)", p->coef, p->expn);
			}
			else if (p->coef == 1)
			{
				printf("+x^(%d)", p->expn);
			}
			else if (p->expn == 1)
			{
				printf("+%.1fx", p->coef);
			}
			else if (p ->expn == 0)
			{
				printf("+%.1f", p->coef);
			}
			else
			{
				printf("+%.1fx^(%d)", p->coef, p->expn);
			}	
		}
		p = p->next;
	}
	printf("\n");
	return OK;
}

Status main(void)
{
	int m;
	polynomail Pa, Pb;
	InitPolyn(&Pa);
	InitPolyn(&Pb);
	printf("请输入要输入Pa的项数:");
	scanf("%d", &m);
	printf("请依次输入Pa中%d组数据:\n", m);
	CreatPolyn(&Pa, m);
	PrintPolyn(Pa);
	printf("请输入要输入Pb的项数:");
	scanf("%d", &m);
	printf("请依次输入Pb中%d组数据:\n", m);
	CreatPolyn(&Pb, m);
	PrintPolyn(Pb);
	AddPolyn(&Pa, &Pb);
	printf("多项式Pa和Pb相加的结果为:\n");
	PrintPolyn(Pa);

	return 0;
}