mypoly.c

多项式求和的计算

#include<stdio.h>
#include<malloc.h>
struct dxs
{
   int zhs;
   float xis;
   struct dxs *next;
}*L1,*L2;

void main()
{
  struct dxs * initList(struct dxs *L);
  struct dxs *inputPoly(struct dxs *L);
  struct dxs *insertElemt(struct dxs *L,int zhs,float xis);
  void showList(struct dxs *L);
  void welcome(void);
  struct dxs* mergList(struct dxs *L1,struct dxs *L2);

  welcome();
  printf("================Please input the first Poly================\n");
  L1=initList(L1);/*初始化表*/
  L1=inputPoly(L1);/*插入新的多项式*/
  showList(L1);/*显示多项式*/
  printf("=============Please input the second Poly================\n");
  L2=initList(L2);/*初始化表*/
  L2=inputPoly(L2);/*插入新的多项式*/
  showList(L2);/*显示多项式*/

   /*合并两个多项式*/
    printf("===============Printf the result=================\n");
  showList(mergList(L1,L2));

 }

 void welcome()
 {
    printf("\t***********************************************\n");
    printf("\t*\tPlease input XiShu ZhiShu\t      *\n");
    printf("\t*\tAs this format xishu,zhishu\t      *\n");
    printf("\t*\tEnd inputing with \"Q\"\t\t      *\n");
    printf("\t*\t==Designed by Zhao Chao== \t      *\n");
    printf("\t***********************************************\n");
 }

 struct dxs * initList(struct dxs *L)
 {
    /*创建带头结点的链表*/
    L=(struct dxs *)malloc(sizeof(struct dxs));
    L->next=NULL;
    return L;
 }

 /*插入新的多项式信息*/
 struct dxs *inputPoly(struct dxs *L)
 {
    char end;
    int zhs;
    float xis;
    struct dxs *newL=L;

   while(end!='Q')
   {
     scanf("%f,%d",&xis,&zhs);
     newL=insertElemt(newL,zhs,xis);
     end=getchar();
   }
   return newL;
 }

 /*向链表中插入新的元素*/
 struct dxs *insertElemt(struct dxs *L,int zhs,float xis)
 {
     struct dxs *newdxs=(struct dxs *)malloc(sizeof(struct dxs));
     newdxs->zhs=zhs;
     newdxs->xis=xis;
     newdxs->next=L->next;
     L->next=newdxs;
     return L;
 }

 /*显示多项式*/
  void showList(struct dxs *L)
  {
      struct dxs *p=L->next;
      char y[]={"f(x)="};
      int nodenum=1;
      printf("%s",y);
      while(p)
      {
        switch(nodenum)
        {
           case 1:
            printf("%.2fX%d",p->xis,p->zhs);
            break;
           default:
            printf("+%.2fX%d\n",p->xis,p->zhs);
            break;
        }
        p=p->next;
        nodenum++;
      }
      getch();
  }

  /*
    合并两个多项式
    通过对L2中的每个元素与L1所有的元素扫描，找出指数相等的,
    不等的对L1进行插入删除操作
    */
  struct dxs* mergList(struct dxs *L1,struct dxs *L2)
  {
     struct dxs* pa,*pb,*priora,*insertnode;
     pa=L1->next;pb=L2->next;
     priora=L1;/*记录抵消的节点前一个节点*/

     while(pb)
     {
        /*除非找见指数相等的进行处理，然后跳出，否则一次扫描后pa=NULL*/
        while(pa)
        {
          if(pb->zhs==pa->zhs)/*指数相等的项*/
          {
            if(pb->xis+pa->xis==0)/*系数绝对值相等符号相反*/
            {
                /*抵消项*/
               priora->next=pa->next;
               break;

            }
            else
            {

                pa->xis=pa->xis+pb->xis; /*系数不等系数相加*/
                break;
            }
          }
          priora=pa;/*用于记录合并不同项时记录当前节点的前驱*/
          pa=pa->next;
        }
        /*查找了整个L1表没有找到与当前pb指数相等的项*/
        if(pa==NULL)
        {
        /*新创建一个与当前pb内容相同的元素，并将其连接到L1的末尾*/
            insertnode=(struct dxs *)malloc(sizeof(struct dxs));
            insertnode->zhs=pb->zhs;
            insertnode->xis=pb->xis;
            insertnode->next=pa;
            priora->next=insertnode;
        }
        /*将pa及其前驱重初始化，以便下一个pb元素扫描整个L1表*/
        priora=L1;
        pa=L1->next;


        pb=pb->next;

     }
     free(pb);
     return L1;
  }