duoxiangshi.rar_读取多项式

#include<stdio.h> #include<malloc.h> typedef struct Polynomial{ float coef; int expn; struct Polynomial *next; }*Polyn,Polynomial; void Insert(Polyn p,Polyn h){ if(p->coef==0) free(p); else{ Polyn q1,q2; q1=h;q2=h->next; while(q2&&p->expn<q2->expn){ q1=q2; q2=q2->next; } if(q2&&p->expn==q2->expn){ q2->coef+=p->coef; free(p); if(!q2->coef){ q1->next=q2->next; free(q2); } } else{ p->next=q2; q1->next=p; } } }//Insert Polyn CreatePolyn(Polyn head,int m){ int i; Polyn p; p=head=(Polyn)malloc(sizeof(struct Polynomial)); head->next=NULL; for(i=0;i<m;i++){ p=(Polyn)malloc(sizeof(struct Polynomial)); printf("请输入第%d项的系数与指数:",i+1); scanf("%f %d",&p->coef,&p->expn); Insert(p,head); } return head; }//CreatePolyn void DestroyPolyn(Polyn p){ Polyn q1,q2; q1=p->next; q2=q1->next; while(q1->next){ free(q1); q1=q2; q2=q2->next; } } void PrintPolyn(Polyn P){ Polyn q=P->next; int flag=1; if(!q) { putchar('0'); printf("\n"); return; } while (q){ if(q->coef>0&&flag!=1) putchar('+'); if(q->coef!=1&&q->coef!=-1){ printf("%g",q->coef); if(q->expn==1) putchar('X'); else if(q->expn) printf("X%d",q->expn); } else{ if(q->coef==1){ if(!q->expn) putchar('1'); else if(q->expn==1) putchar('X'); else printf("X%d",q->expn); } if(q->coef==-1){ if(!q->expn) printf("-1"); else if(q->expn==1) printf("-X"); else printf("-X%d",q->expn); } } q=q->next; flag++; }//while printf("\n"); }//PrintPolyn int compare(Polyn a,Polyn b){ if(a&&b){ if(!b||a->expn>b->expn) return 1; else if(!a||a->expn<b->expn) return -1; else return 0; } else if(!a&&b) return -1; else return 1; }//compare Polyn AddPolyn(Polyn pa,Polyn pb){ Polyn qa=pa->next; Polyn qb=pb->next; Polyn headc,hc,qc; hc=(Polyn)malloc(sizeof(struct Polynomial)); hc->next=NULL; headc=hc; while(qa||qb){ qc=(Polyn)malloc(sizeof(struct Polynomial)); switch(compare(qa,qb)){ case 1: { qc->coef=qa->coef; qc->expn=qa->expn; qa=qa->next; break; } case 0: { qc->coef=qa->coef+qb->coef; qc->expn=qa->expn; qa=qa->next; qb=qb->next; break; } case -1: { qc->coef=qb->coef; qc->expn=qb->expn; qb=qb->next; break; } }//switch if(qc->coef!=0){ qc->next=hc->next; hc->next=qc; hc=qc; } else free(qc);//当相加系数为0时，释放该结点 }//while return headc; }//AddPolyn Polyn SubtractPolyn(Polyn pa,Polyn pb){//求解并建立多项式a+b，返回其头指针 Polyn h=pb; Polyn p=pb->next; Polyn pd; while(p){ //将pb的系数取反 p->coef*=-1; p=p->next; } pd=AddPolyn(pa,h); for(p=h->next;p;p=p->next) //恢复pb的系数 p->coef*=-1; return pd; }//SubtractPolyn int main(){ int m,n,flag=0; float x; Polyn pa=0,pb=0,pc,pd,pe,pf;//定义各式的头指针，pa与pb在使用前付初值NULL printf("请输入a的项数:"); scanf("%d",&m); pa=CreatePolyn(pa,m);//建立多项式a printf("请输入b的项数:"); scanf("%d",&n); pb=CreatePolyn(pb,n);//建立多项式a //输出菜单 printf("**********************************************\n"); printf("操作提示：\n\t1.输出多项式a和b\n\t2.建立多项式a+b\n\t3.建立多项式a-b\n"); printf("\t4.退出\n**********************************************\n"); for(;;flag=0){ printf("执行操作："); scanf("%d",&flag); if(flag==1){ printf("多项式a：");PrintPolyn(pa); printf("多项式b：");PrintPolyn(pb);continue; } if(flag==2){ pc=AddPolyn(pa,pb); printf("多项式a+b：");PrintPolyn(pc); DestroyPolyn(pc);continue; } if(flag==3){ pd=SubtractPolyn(pa,pb); printf("多项式a-b：");PrintPolyn(pd); DestroyPolyn(pd);continue; } if(flag==4) break; if(flag<1||flag>4) printf("Error!!!\n");continue; }//for DestroyPolyn(pa); DestroyPolyn(pb); return 0; }