单链表实现多项式怎么改成循环单链表来实现

Question

#include
#include

//poly数据类型
typedef struct poly
{
int coef;
int expn;
struct poly *pnext;
} POLY;

//初始化表达式
POLY *InitPoly(void)
{
POLY *phead;
if ((phead = (POLY *)malloc(sizeof(POLY))) == NULL)
exit(-1);
phead->pnext = NULL;
return phead;
}

//输入表达式
void InputPoly(POLY *phead)
{
int coef,expn;
POLY *ptail,*pnew;
ptail = phead;
while(1)
{
scanf("%d,%d", &coef, &expn);
if (coef != 0)
{
if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
exit(-1);
pnew->coef = coef;
pnew->expn = expn;
ptail->pnext = pnew;
ptail = pnew;
}
else
{
break;
}
}

ptail->pnext = NULL;

}

//输出表达式
void OutputPoly(POLY *phead)
{
POLY *ptemp;
ptemp = phead->pnext;

if (ptemp == NULL)
{
    printf("\n");
    return;
}
printf("%dx^%d", ptemp->coef, ptemp->expn);
ptemp = ptemp->pnext;

while(ptemp != NULL)
{
    printf("+%dx^%d", ptemp->coef, ptemp->expn);
    ptemp = ptemp->pnext;
}
printf("\n");

}

//表达式相加
POLY *AddPoly(POLY *pheadA, POLY *pheadB)
{
int temp;
POLY *pheadC, *pnew, *ptail; //结果链表相关变量
POLY *ptempA, *ptempB; //运算链表相关变量

ptempA = pheadA->pnext;
ptempB = pheadB->pnext;
pheadC = InitPoly();
ptail = pheadC;

//将两个多项式扫描运算后放入结果链表中
while(ptempA != NULL && ptempB != NULL)
{
    //如果指数相等
    if (ptempA->expn == ptempB->expn)
    {

        if ((temp = ptempA->coef + ptempB->coef) == 0)
        {
            ptempA = ptempA->pnext;
            ptempB = ptempB->pnext;
            continue;
        }
        if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
            exit(-1);
        pnew->coef = temp;
        pnew->expn = ptempA->expn;
        ptail->pnext = pnew;
        pnew->pnext = NULL;
        ptail = pnew;
        ptempA = ptempA->pnext;
        ptempB = ptempB->pnext;

    }//如果多项式A指数小于B
    else if(ptempA->expn < ptempB->expn)
    {
        if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
            exit(-1);
        *pnew = *ptempA;
        pnew->pnext = NULL;
        ptail->pnext = pnew;
        ptail = pnew;
        ptempA = ptempA->pnext;
    }//如果多项式A指数大于B
    else
    {
        if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
            exit(-1);
        *pnew = *ptempB;
        pnew->pnext = NULL;
        ptail->pnext = pnew;
        ptail = pnew;
        ptempB = ptempB->pnext;
    }
}
//将剩余的未扫描项放入结果链表中
while(ptempA != NULL)
{
    if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
        exit(-1);
    *pnew = *ptempA;
    pnew->pnext = NULL;
    ptail->pnext = pnew;
    ptail = pnew;
    ptempA = ptempA->pnext;
}
while(ptempB != NULL)
{
    if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
        exit(-1);
    *pnew = *ptempB;
    pnew->pnext = NULL;
    ptail->pnext = pnew;
    ptail = pnew;
    ptempB = ptempB->pnext;
}
return pheadC;

}

//多项式求导
POLY *DerPoly(POLY *phead)
{
POLY *ptemp = phead->pnext;
POLY *pnew, *pheadX, *ptail;
pheadX = InitPoly();
ptail = pheadX;
while(ptemp != NULL)
{
if (ptemp->expn == 0)
{
ptemp = ptemp->pnext;
continue;
}
if ((pnew = (POLY *)malloc(sizeof(POLY))) == NULL)
exit(-1);
pnew->coef = ptemp->coef * ptemp->expn;
pnew->expn = ptemp->expn - 1;
ptail->pnext = pnew;
pnew->pnext = NULL;
ptail = pnew;
ptemp = ptemp->pnext;
}
return pheadX;
}

int main(void)
{
POLY *pheadA, *pheadB, *result;
pheadA = InitPoly();
printf("请输入多项式A(系数,指数),需指数递增输入,系数为0时结束输入:\n");
InputPoly(pheadA);

pheadB = InitPoly();
printf("请输入多项式B(系数,指数),需指数递增输入,系数为0时结束输入:\n");
InputPoly(pheadB);

printf("多项式A：");
OutputPoly(pheadA);
printf("多项式B：");
OutputPoly(pheadB);

result = AddPoly(pheadA, pheadB);
printf("多项式A + 多项式B = ");
OutputPoly(result);

printf("多项式A求导 = ");
result = DerPoly(pheadA);
OutputPoly(result);

printf("多项式B求导 = ");
result = DerPoly(pheadB);
OutputPoly(result);

return 0;

}

Answer 1

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