开发笔记:对一元多项式的加减以及求导运算的实现

#include
#include
typedef struct
{
float coef;//系数
int expn;//指数
struct UNARY *next;
} UNARY;
float add_ab(float A,float B)
{
return A+B;
}
float subtract_ab(float A,float B)
{
return A - B;
}
//升幂的一元多项式的相加与相减
UNARY* unaryAdd_Sub(UNARY *LA,UNARY *LB,char method)
{
//LA作为输出链
UNARY *r,*s,*p,*q;
int cmp;
p = LA->next;//用于比较
q = LB->next;//用于比较
s = LA;//用于记录p的前置
r = LB;//用于记录q的后置
while(p!=NULL && q!=NULL)
{
if(p->expnexpn) cmp = -1;//当p指数小于q指数，p后移
else if(p->expn>q->expn) cmp = 1;//当p指数大于q指数，q为p的前置，q后移
else cmp = 0;//pq指数相同，进行加/减运算
switch(cmp)
{
case -1:
{
s = p;
p = p->next;
};
break;
case 0:
{
float x;
if(method == \'+\')
{
x = add_ab(p->coef,q->coef);
}
else if(method == \'-\')
{
x = subtract_ab(p->coef,q->coef);
}
if((int)x!=0)
{
p->coef = x;
s = p;
p = p->next;
r->next =q->next;
free(q);
q = r->next;
}
else
{
//删除LA节点
s->next = p->next;
free(p);
p = s->next;
//删除LB节点
r->next =q->next;
free(q);
q = r->next;
}
};
break;
case 1:
{
r->next = q->next;
q->next = s->next;
s->next = q;
s = q;
q = r->next;
};
break;
}
}
if(q!=NULL)
{
//因为 前面的结束条件 p = null 所以 p的前置s位于链表的尾部，s连接q
s->next = q;
}
free(LB);
return LA;

}
UNARY* creatList(UNARY *LA,UNARY *LB)
{
LA->next = NULL;
LB->next = NULL;
UNARY *node;
int choice;
int i = 1;
while(1)
{
printf("输入LA序列的第%d元素的系数+指数（格式：系数 指数）",i);
node = (UNARY*)malloc(sizeof(UNARY));
if(node==NULL)
{
exit(0);
}
scanf("%f %d",&node->coef,&node->expn);
//不合法分析：1、系数为零 （√）2、指数重复（未解决）
if(node->coef==0)
{
continue;
}
node->next = LA->next;
LA->next = node;
i++;
printf("继续？（1,0）");
scanf("%d",&choice);
if(choice==0)
{
break;
}
}
while(1)
{
printf("输入LB序列的第%d元素的系数+指数（格式：系数 指数）",i);
node = (UNARY*)malloc(sizeof(UNARY));
scanf("%f %d",&node->coef,&node->expn);
node->next = LB->next;
LB->next = node;
i++;
printf("继续？（1,0）");
scanf("%d",&choice);
if(choice==0)
{
break;
}
}
}
UNARY* printList(UNARY *LA,UNARY *LB)
{
UNARY *circleLA,*circleLB;
circleLA = LA;
circleLB = LB;
printf("LA:\\n");
while(circleLA->next!=NULL)
{
circleLA = circleLA->next;
printf("%.2f %d\\n",circleLA->coef,circleLA->expn);
}
printf("LB:\\n");
while(circleLB->next!=NULL)
{
circleLB = circleLB->next;
printf("%.2f %d\\n",circleLB->coef,circleLB->expn);
}
}
/*对一元多项式进行升幂排序
*输入：一元多项式链表
*输出：升幂排序的一元多项式链表
*
*/
UNARY* Increasing(UNARY *LA,UNARY *LB)
{
UNARY *head,*end,*pre,*cur,*next,*temp;
head = LA;
end = NULL;
//冒泡排序：将 最小/最大 的节点后移至当前的最后一位。
while(head->next != end)
{
for(pre = head,cur = head->next,next = cur->next; next != end; pre = pre->next,cur = cur->next,next = next->next)
{
if(cur->expn > next->expn)
{
cur->next = next->next;
pre->next = next;
next->next = cur;
temp = next;
next = cur;
cur = temp;
}
}
end = cur;
}
head = LB;
end = NULL;
while(head->next != end)
{
for(pre = head,cur = head->next,next = cur->next; next != end; pre = pre->next,cur = cur->next,next = next->next)
{
if(cur->expn > next->expn)
{
cur->next = next->next;
pre->next = next;
next->next = cur;
temp = next;
next = cur;
cur = temp;
}
}
end = cur;
}

}
/*对一元多项式进行求导
*输入：一元多项式链表
*输出：求导后的一元多项式链表
*所谓求导系数与指数相乘，指数减1；如果指数为零，本项为零，不再复制到新的多项式中
*/
UNARY* Derivation(UNARY *LA,UNARY *LB)
{
UNARY *headLA,*headLB;
headLA = LA;
headLB = LB;
while(headLA->next!=NULL)
{
headLA = headLA->next;
headLA->coef = headLA->coef*headLA->expn;
if(headLA->expn!=0)
{
headLA->expn -= 1;
}
else
{
headLA->expn = 0;
}
}
while(headLB->next!=NULL)
{
headLB = headLB->next;
headLB->coef = headLB->coef*headLB->expn;
if(headLB->expn!=0)
{
headLB->expn -= 1;
}
else
{
headLB->expn = 0;
}
}
}
int main()
{
int choice;
//创建链表
UNARY *LA,*LB;
LA = (UNARY*)malloc(sizeof(UNARY));
LB = (UNARY*)malloc(sizeof(UNARY));
creatList(LA,LB);
//将链表变为升幂次序
Increasing(LA,LB);
printf("升幂后\\n");
printList(LA,LB);
printf("输入选择（1：求导 2：运算）:");
scanf("%d",&choice);
if(choice ==1)
{
//求导：将系数与指数相乘 然后指数减1
Derivation(LA,LB);
printf("求导后\\n");
printList(LA,LB);
}
else if(choice == 2)
{
//运算(加减运算)
char x;
printf("运算：");
scanf("\\n");
scanf("%c",&x);
unaryAdd_Sub(LA,LB,x);
printf("运算后\\n");
printList(LA,NULL);
}



}