改动第一次

10.14（宋）

+#include<stdio.h>
+#include<malloc.h>
+
+typedef struct Polynomial
+{
+	float coef;//系数
+	int exp;//指数
+	struct Polynomial *next;//指针域 
+}*Poly,Polynomial;
+
+void Insert(Poly p,Poly head)      //插入
+{
+ if(p->coef==0)         //系数为0时释放结点
+ free(p);
+ else
+ {
+  Poly q1,q2;
+  q1=head;
+  q2=head->next;
+  while(q2&&p->exp<q2->exp)     //后移查找插入位置
+  {
+   q1=q2;
+   q2=q2->next;
+  }
+  if(q2&&p->exp==q2->exp)      //将指数相同的相合并
+  {
+   q2->coef+=p->coef;
+   free(p);
+   if(!q2->coef)       //系数为0时释放结点
+   {
+    q1->next=q2->next;
+    free(q2);
+   }  
+   //p->next=q2;
+   //q1->next=p;
+  }
+  else
+  {
+   p->next=q2;
+   q1->next=p;
+  }
+ }
+}
+
+ 
+
+Poly CreateList(Poly head,int m)     //建立一个头指针为head、项数为m的一元多项式
+{
+ int i;
+ Poly p;
+ Polynomial *q;
+ p=head=(Poly)malloc(sizeof(struct Polynomial));
+ head->next=NULL;
+ for(i=0;i<m;i++)
+ {
+  p=(Poly)malloc(sizeof(struct Polynomial)); //建立新结点以接收数据
+  printf("请输入第%d项的系数与指数: \n",&i+1);
+  scanf("%f %d",&p->coef,&p->exp);
+  Insert(p,head);        //调用Insert函数插入结点
+ }
+ return head;
+}
+
+ 
+
+int OutputList(Poly P)        //输出多项式
+{
+ Poly q=P->next;
+ int flag=1;          //项数计数器
+ if(!q)
+ {            //若多项式为空，输出0
+  printf(" 0 \n");
+  return(0);
+ }
+ while (q)
+ {
+  if(q->coef>0&&flag!=1)      //系数大于0且不是第一项
+  printf("+");
+  if(q->coef!=1&&q->coef!=-1)     //系数非1或-1的普通情况
+  {
+   printf("%f",&q->coef);
+   if(q->exp==1)
+   printf("X");
+   else if(q->exp)
+   printf("X^%d",&q->exp);
+  }
+  else
+  {
+   if(q->coef==1)
+   {
+    if(!q->exp)
+    printf("1");
+    else if(q->exp==1)
+    printf("X");
+    else if(q->exp)
+    printf("X^%d",&q->exp);
+   }
+   if(q->coef==-1)
+   {
+    if(!q->exp) printf("-1");
+    else if(q->exp==1) printf("-X");
+    else printf("-X^%d",&q->exp);
+   }
+  }
+  q=q->next;
+  flag++;
+ }
+ printf("\n");
+ return(0);
+}
+
+ 
+
+int compare(Poly a,Poly b)
+{
+ if(a&&b)
+ {
+  if(!a||a->exp>b->exp) return 1;
+  else if(!b||a->exp<b->exp) return -1;
+  else return 0;
+ }
+ else if(!a&&b) return -1;      //a多项式已空，但b多项式非空
+ else return 1;         //b多项式已空，但a多项式非空
+}
+
+
+Poly AddPoly(Poly pa,Poly pb)      //求解并建立和多项式a+b，返回其头指针
+{
+ Poly qa=pa->next;
+ Poly qb=pb->next;
+ Poly headc,hc,qc;
+
+ hc=(Poly)malloc(sizeof(struct Polynomial));  //建立头结点
+ hc->next=NULL;
+ headc=hc;
+ while(qa||qb)
+ {
+  qc=(Poly)malloc(sizeof(struct Polynomial));
+  switch(compare(qa,qb))
+  {
+   case 1:
+   {
+    qc->coef=qa->coef;
+    qc->exp=qa->exp;
+    qa=qa->next;
+    break;
+   }
+   case 0:
+   {
+    qc->coef=qa->coef+qb->coef;
+    qc->exp=qa->exp;
+    qa=qa->next;
+    qb=qb->next;
+    break;
+   }
+   case -1:
+   {
+    qc->coef=qb->coef;
+    qc->exp=qb->exp;
+    qb=qb->next;
+    break;
+   }
+  }
+ 
+  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
+ }
+ return headc;
+}
+
+int main()
+{
+ int m,n,flag=0;
+ float x;
+ Poly 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("    输入多项式a和b:     \n"); 
+
+ printf("请输入a的项数:\n");      //建立多项式a
+ scanf("%d",&m);
+ if(!scanf)
+ {
+  printf("\n\n");
+  printf("输入为小数英文或者其他字符,输入错误,退出!\n");
+  printf("\n\n");
+ }
+ pa=CreateList(pa,m);      
+
+ printf("请输入b的项数:\n") ;      //建立多项式b
+ scanf("%d",&n);
+ if(!scanf)
+ {
+  printf("\n\n");
+  printf("输入为小数英文或者其他字符,输入错误,退出!\n");
+  printf("\n\n");
+ }
+ pb=CreateList(pb,n);
+
+ printf("\n\n");
+ printf("多项式a和b为：\n");
+ OutputList(pa);
+ OutputList(pb);
+
+ printf("***************************************\n\n");
+
+ printf("          1.输出多项式a     \n");
+ printf("          2.输出多项式b     \n");
+ printf("          3.输出多项式a+b   \n");
+ printf("          0.退出程序        \n\n");
+
+ printf("***************************************\n");
+ for(;;flag=0)
+ {
+  printf("执行操作为:");
+  scanf("%d",&flag);
+  
+  if(flag==1)
+  {
+   if(pa)
+   {
+    printf("多项式a为：");
+    OutputList(pa);
+    
+   }
+   else
+   {
+    printf("0\n");
+   }
+   continue;
+  }
+  if(flag==2)
+  {
+   printf("多项式b为：");
+   OutputList(pb);
+   continue;
+  }
+  if(flag==3)
+  {
+   pc=AddPoly(pa,pb);
+   printf("多项式a+b为：");
+   OutputList(pc);
+   continue;
+  }
+  if(flag==0)
+   break;
+
+  if(flag<0||flag>7)
+  printf("输入错误!!!请重新选择!!");
+  continue;
+ }
+ return 0;
+}
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