一元多项式表示和相加

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

typedef struct LNode {
ElemType data;
struct LNode *next;
}*Link,*Position;

typedef struct {
Link head;
Link tail;
int len;
} LinkList

/*----------------------------------------------------------------
* file:poly.h -->the head file for Polynominal.c
* date:9-19-2014
* author: doodlesomething@163.com
* version:1.0
* description:线性链表实现一元多项式的相加减乘运算
-----------------------------------------------------------------*/

#define TRUE 1
#define FALSE 0
#define OVERFLOW -2
#define OK 1
#define ERROR 0

typedef int Status;

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

typedef struct LNode {
ElemType data;
struct LNode *next;
}*Link,*Position;

typedef struct {
Link head;
Link tail;
int len;
} LinkList;

typedef  LinkList Poly;

//初始化链表
Status InitList(Poly *Po);

//获取头节点
Position GetHead(Poly Po);

//更新元素
void SetCurElem(Link h,ElemType e);

//创建二项式
void CreatePoly(Poly *Po,int n);

//在第一个节点前插入
void InsFirst(Poly *Po,Link q,Link s);

//创建节点
Status MakeNode(Link *s,ElemType e);

//定位元素
Status LocateElem(Poly Po,ElemType e,Link *q,Status (*compare) (ElemType,ElemType));

//比较两元素
Status compare(ElemType ta,ElemType tb);

//输出
void PrintPoly(Poly Po);

//添加
void AddPoly(Poly *Pa,Poly *Pb);

//添加元素
void Append(Poly *Po,Link pb);

//下一个点的指针
Position NextPos(Link p);

//删除第一个元素
Status DeleFirst(Poly *Po,Link h,Link *p);

//释放节点
void FreeNode(Link p);

//获取当前元素值
ElemType GetCurElem(Link p);

//判空
Status ListEmpty(Poly Po);

/*----------------------------------------------------------------
* file:Polynominal.c
* date:9-19-2014
* author: doodlesomething@163.com
* version:1.0
* description:线性链表实现一元多项式的相加减乘运算
* attentio :这里没有输入检测
-----------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include "poly.h"

/*
* @description:初始化空链表
* @param Poly Po
* @return Status
*/
Status InitList(Poly *Po) {

Link p;
p = (Link) malloc(sizeof(struct LNode));

if(p != NULL) {
p->next = NULL;
(*Po).head = (*Po).tail = p;
(*Po).len = 0;
return OK;
}
return ERROR;
}

int ListLength(Poly Po) {
return Po.len;
}

/*
* @description 返回头结点
* @param Poly Po
* @return Postion head
*/
Position GetHead(Poly Po){
return Po.head;
}

/*
* @description 设置头结点的值
*/
void SetCurElem(Link h,ElemType e)  {
h->data = e;
}

/*
* @description 创建多项式链表
* @param Poly Po
* @param int n
* @return void
*/
void CreatePoly(Poly *Po,int n) {
InitList(Po);

Position q,s,h;
int i;

term e;

h = GetHead(*Po);
e.coef = 0;
e.expn = -1;

SetCurElem(h,e);

printf("Please enter %d coef,expn:\n",n);

for(i = 0; i < n; i++) {
scanf("%d,%d;",&e.coef,&e.expn);

if(!LocateElem(*Po,e,&q,compare)) {
if(MakeNode(&s,e))
InsFirst(Po,q,s);
}
}
}

/*
* @description 将生成的节点插入链表中
*/
void InsFirst(Poly *Po,Link q,Link s) {
s->next = q->next;
q->next = s;

(*Po).len++;

if(q == (*Po).tail)
(*Po).tail = q->next;
}

/*
* @description 为新加入的元素创建节点
*/
Status MakeNode(Link *s,ElemType e) {
(*s) = (Link) malloc(sizeof(struct LNode));

if( (*s) != NULL) {
(*s)->data = e;
(*s)->next = NULL;
return OK;
}

return ERROR;
}

/*
* @description 判断该元素在P中是否存在，倘若存在则返回TRUE及该位置，否则返回第一个compare >0的前驱位置
*/
Status LocateElem(Poly Po,ElemType e,Link *q,Status (*compare) (ElemType,ElemType)) {
Link p,pre;

p = Po.head;

do {
pre = p;
p = p->next;
}while(p != NULL && compare(p->data,e) < 0);

if(p == NULL || compare(p->data,e) > 0) {
(*q) = pre;
return FALSE;
}
else {
(*q) = p;
return TRUE;
}
}

/*
* @description 比较ta,tb两个元素的大小
*/
Status compare(ElemType ta,ElemType tb) {
if(ta.expn > tb.expn)
return 1;
else if(ta.expn == tb.expn)
return 0;
else
return -1;
}

/*
* @descrption 打印链表
*/
void PrintPoly(Poly Po) {
Link p;

p = Po.head->next;

printf("\t\t系数    指数:\n");

while(p != NULL) {
printf("\t\t %d        %d\n",p->data.coef,p->data.expn);
p = p->next;
}

}

/*
* @description 二项式相加
* @param Poly *Pa
* @param Poly *Pb
* @return void
* @detail a,b多项式相加有三种情况：
1.a的指数小于b的指数，则将a的指针向后移动，
2.a的指数等于b的指数,则两者的系数相加的sum，
2.1 sum等于0,则删除a,b两节点，并将两者的指针后移
2.2 sum不等于0,则将a节点的coef更新，删除b节点，两指针后移
3.a的指数大于b的指数，将b插入在a之前,删除b节点,指针后移
*/
void AddPoly(Poly *Pa,Poly *Pb) {
//ha的作用类似与前驱节点，方便删除节点
Link ha,hb,pa,pb;
term ta,tb;
int sum;

ha = GetHead(*Pa);
hb = GetHead(*Pb);

pa = NextPos(ha);
pb = NextPos(hb);

while(pa && pb) {
ta = GetCurElem(pa);
tb = GetCurElem(pb);

switch(compare(ta,tb)) {
case -1:
ha = pa;
pa = NextPos(ha);
break;
case 0:
sum = pa->data.coef + pb->data.coef;

if(sum != 0) {
pa->data.coef = sum;
SetCurElem(pa,pa->data);
ha = pa;
}
else {
DeleFirst(Pa,ha,&pa);
FreeNode(pa);
}

DeleFirst(Pb,hb,&pb);
FreeNode(pb);
pa = NextPos(ha);
pb = NextPos(hb);
break;
case 1:
printf("%d\n",DeleFirst(Pb,hb,&pb));
InsFirst(Pa,ha,pb);
FreeNode(pb);
ha = NextPos(ha);
pb = NextPos(hb);
break;
}
}

if(!ListEmpty(*Pb))
Append(Pa,pb);
//将Pb头结点释放
FreeNode(hb);
}

//将剩余的链接到Pa中
void Append(Poly *Po,Link pb) {
int i;

i = 0;
(*Po).tail->next = pb;

while(pb) {
pb = pb->next;
i++;
}

(*Po).tail = pb;
(*Po).len += i;
}

//返回下一个节点的位置
Position NextPos(Link p) {
return p->next;
}

//删除节点
Status DeleFirst(Poly *Po,Link h,Link *p) {
(*p) = h->next;
if(*p) {
h->next = (*p)->next;
if(!h->next)
(*Po).tail = h;

(*Po).len--;
return OK;
}
else
return ERROR;

}

//释放节点
void FreeNode(Link p) {
free(p);
p = NULL;
}

//获取当前节点的值
ElemType GetCurElem(Link p) {
return p->data;
}

/*
* @description 判空
*/
Status ListEmpty(Poly Po) {
return Po.len > 0 ? FALSE : TRUE;
}

#include <stdio.h>
#include <stdlib.h>
#include "poly.h"

int main(int argc,char *argv[]) {
Poly Pa,Pb;
int b,option,n;

b = 1;

while(b)  {
printf("-----------一元多项式的运算------------------------\n");
printf("      <0>创建A  <1>创建B   <2>相加     \n");
printf("        <5>打印A   <6>打印B   <7>退出  \n");
printf("Please option the menu:");
scanf("%d",&option);

switch(option) {
case 0:
printf("Please enter the length of the PolyA:");
scanf("%d",&n);
CreatePoly(&Pa,n);
break;
case 1:
printf("Please enter the length of the PolyB");
scanf("%d",&n);
CreatePoly(&Pb,n);
break;
case 2:
AddPoly(&Pa,&Pb);
break;
case 3:
//SubtractPoly(Pa,Pb);
break;
case 4:
//MultiplyPoly(Pa,Pb);
break;
case 5:
printf("PolyA:");
PrintPoly(Pa);
break;
case 6:
printf("PolyB");
PrintPoly(Pb);
break;
case 7:
b = 0;
printf("Exiting\n");
break;
default:
fprintf(stderr,"Sorry something wrong with your option:%d\n",option);
break;
}
}

exit(0);
}