一元多项式相加的链式实现

#include"PLOY.h"


#include<stdio.h>
#include<stdlib.h>
#include<assert.h>


//动态申请结点


NODE * alloc_node(int coef,int exp)
{
NODE * tmp = (NODE *)malloc(sizeof(NODE));
assert(tmp);
tmp ->coef = coef;
tmp ->exp = exp;
tmp->next = NULL;
return tmp;
}




//创建有序一元多项式


NODE *create_ploy()
{
NODE *phead = alloc_node(0,0);


int coef;
int exp;


NODE *tmp;
NODE *s;
NODE *p;


while(1)//同指数合并（未考虑）
{
printf("请输入多项式（输入0,0表示停止输入）\n");
scanf("%d,%d",&coef,&exp);
if (coef == 0 && exp == 0)
{
break;
}
if (coef == 0)
{
continue;
}


tmp = alloc_node(coef,exp);
p = phead;
s = phead;
while(p != NULL && p->exp <= tmp->exp)
{
s = p;
p = p->next;
}
tmp->next = p;
s->next = tmp;
}
return phead;
}


//一元多项式判空
bool is_empty(NODE *phead)
{
if (phead == NULL)
{
return false;
}
return phead->next == NULL;
}




//一元多项式合并同类项
bool create_final_ploy(NODE *phead)
{
if (phead == NULL || is_empty(phead))
{
return false;
}
NODE *r = phead;
NODE *p = phead->next;
NODE *s = phead->next;


while (p->next != NULL)
{
p = p->next;
if (p->exp == s->exp)
{
p->coef = p->coef + s->coef;
r->next = p;
free(s);
}
s = p;
}
return true;
}


//输出显示一元多项式
void show_ploy(NODE *phead)
{
NODE *p = phead->next;
while(p != NULL)
{
if (p->coef > 0)
{
printf(" +%dx^%d ",p->coef,p->exp);
}
else
{
printf(" %dx^%d ",p->coef,p->exp);
}
p = p->next;
}
printf("\n");
}




//一元多项式合并
NODE *add_ploy(NODE *pa, NODE *pb)
{
NODE *pc = alloc_node(0,0);


NODE *p = pa->next;
NODE *s = pb->next;
NODE *r = pc;


NODE *tmp;


while(p != NULL && s != NULL)
{
if (p->exp < s->exp)
{
tmp = alloc_node(p->coef,p->exp);
r->next = tmp;
r= tmp;
p = p->next;
}
else if(p->exp > s->exp)
{
tmp = alloc_node(s->coef,s->exp);
r->next = tmp;
r= tmp;
s = s->next;
}
else
{
tmp = alloc_node(p->coef+s->coef,p->exp);
r->next = tmp;
r= tmp;
p = p->next;
s = s->next;
}
}




while(p != NULL)
{
tmp = alloc_node(p->coef,p->exp);
r->next = tmp;
r= tmp;
p = p->next;
}


while(s != NULL)
{
tmp = alloc_node(s->coef,s->exp);
r->next = tmp;
r= tmp;
s = s->next;
}


return pc;
}




//销毁一元多项式
bool destory_ploy(NODE *phead,elem_type *coef,elem_type *exp)
{
if (phead == NULL)
{
return false;
}
NODE *p = phead;
while (p->next != NULL)
{
del_tail_ploy(phead,coef,exp);
}
free(phead);
return true;
}




//尾删一元多项式
bool del_tail_ploy(NODE *phead,elem_type *coef,elem_type *exp)
{
if (phead == NULL || is_empty(phead))
{
return false;
}
NODE *p = phead;
while (p->next->next != NULL)
{
p = p->next;
}
*coef = p->next->coef;
*exp = p->next->exp;
free(p->next);
p->next = NULL;
return true;
}