一元多项式计算器。乘法有关问题
一元多项式计算器。乘法问题
具体错误我会在程序里注释为ERROR。
------解决思路----------------------
修改如下：
缺陷：
1.有内存泄露。
2.输入多项式时，必须按指数从小到大输入。
本帖最后由 a653560991 于 2015-06-01 21:36:35 编辑
数据结构链表练习，编写乘法的时候遇到问题。程序总是崩溃，估计是指针问题。麻烦大家帮我看一下，多谢啦、具体错误我会在程序里注释为ERROR。
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
typedef struct Polynomial
{
int coef;//系数
int expn;//指数
struct Polynomial *next;
}*Poly,Node;
Poly Creat()
{
Node *head,*rear,*s;
int e;
int c;
head = (Poly)malloc(sizeof(Node));
rear = head;//尾插法
printf("请输入一个一元多项式，形如（系数c，指数e，c=0退出）\n");
scanf("%d,%d",&c,&e);
while(c != 0)//c=0则结束
{
s = (Poly)malloc(sizeof(Node));
s->coef = c;
s->expn = e;
rear->next = s;
rear = s;
scanf("%d,%d",&c,&e);
}
rear->next = NULL;
return (head);
}
void show(Poly p)
{
Poly 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("%d",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++;
}
printf("\n");
}
Poly Add(Poly pa,Poly pb)
{
Poly qa = pa->next;
Poly qb = pb->next;
Poly headc,pc,temp;
pc = (Poly)malloc(sizeof(Node));
pc->next = NULL;
headc = pc;
while(qa != NULL && qb != NULL)
{
temp = (Poly)malloc(sizeof(Node));
if(qa->expn < qb->expn)
{
temp->expn = qa->expn;
temp->coef = qa->coef;
qa = qa->next;
}
else if(qa->expn == qb->expn)
{
temp->expn = qa->expn;
temp->coef = qa->coef + qb->coef;
qa = qa->next;
qb = qb->next;
}
else
{
temp->expn = qb->expn;
temp->coef = qb->coef;
qb = qb->next;
}
if(temp->coef != 0)
{
temp->next = pc->next;
pc->next = temp;
pc = temp;
}
else
free(temp);
}
while(qa != NULL)
{
temp = (Poly)malloc(sizeof(Node));
temp->expn = qa->expn;
temp->coef = qa->coef;
qa = qa->next;
temp->next = pc->next;
pc->next = temp;
pc = temp;
}
while(qb != NULL)
{
temp = (Poly)malloc(sizeof(Node));
temp->expn = qb->expn;
temp->coef = qb->coef;
qb = qb->next;
temp->next = pc->next;
pc->next = temp;
pc = temp;
}
return headc;
}
Poly diff(Poly pa,Poly pb)
{
Poly qb = pb->next;
Poly pd = NULL;
pd = (Poly)malloc(sizeof(Node));
pd->next = NULL;
while(qb)
{
qb->coef = -qb->coef;
qb = qb->next;
}
pd = Add(pa,pb);
for(qb = pb->next;qb != NULL;qb = qb->next)
qb->coef *= -1;//存疑
return pd;
}
Poly Cheng(Poly pa,Poly pb)
{
Poly qa = pa->next;
Poly qb = pb->next;
Poly heade,pe,temp;
Poly sum;
pe = (Poly)malloc(sizeof(Node));
sum = (Poly)malloc(sizeof(Node));
sum->next = NULL;
pe->next = NULL;
heade = pe;
if(qa != NULL && qb != NULL)
{
for(qa = pa->next;qa != NULL;qa = qa->next)
{
for(qb = pb->next;qb != NULL;qb = qb->next)
{
temp = (Poly)malloc(sizeof(Node));
temp->coef = qa->coef * qb->coef;
temp->expn = qa->expn + qb->expn;
temp->next = pe->next;
pe->next = temp;
pe = temp;
free(temp);
show(heade);//ERROR,此处会出现问题。使用单步调试来看，heade里面的值是乱码。程序意外终止。若注释掉本句，下一处ERROR也会发生。
printf("qb=qb->next\n");
}
sum = Add(heade,sum);//ERROR，想利用整数求和的办法。sum+=a;但是总是终止。
}
return sum;
}
else
{
heade->next = NULL;
return heade;
}
}
int main()
{
Poly qc;
Poly qd;
Poly qe;
Node *p,*q;
p = Creat();
show(p);
q = Creat();
show(q);
qc = Add(p,q);
printf("加法：");
show(qc);
qd = diff(p,q);
printf("减法：");
show(qd);
qe = Cheng(p,q);
printf("乘法：");
show(qe);
return 0;
}
------解决思路----------------------
修改如下：
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
typedef struct Polynomial
{
int coef;//系数
int expn;//指数
struct Polynomial *next;
}*Poly, Node;
Poly Creat()
{
Node *head, *rear, *s;
int e;
int c;
head = (Poly)malloc(sizeof(Node)); //头节点
rear = head;//尾插法
printf("请输入一个一元多项式，形如（系数c，指数e，c=0退出）\n");
scanf("%d,%d", &c, &e);
while (c != 0)//c=0则结束
{
s = (Poly)malloc(sizeof(Node));
s->coef = c;
s->expn = e;
rear->next = s;
rear = s;
scanf("%d,%d", &c, &e);
}
rear->next = NULL;
return (head);
}
void show(Poly p)
{
Poly 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("%d", 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++;
}
printf("\n");
}
Poly Add(Poly pa, Poly pb)
{
Poly qa = pa->next;
Poly qb = pb->next;
Poly headc, pc, temp;
pc = (Poly)malloc(sizeof(Node));
pc->next = NULL;
headc = pc;
while (qa != NULL && qb != NULL)
{
temp = (Poly)malloc(sizeof(Node));
if (qa->expn < qb->expn)
{
temp->expn = qa->expn;
temp->coef = qa->coef;
qa = qa->next;
}
else if (qa->expn == qb->expn)
{
temp->expn = qa->expn;
temp->coef = qa->coef + qb->coef;
qa = qa->next;
qb = qb->next;
}
else
{
temp->expn = qb->expn;
temp->coef = qb->coef;
qb = qb->next;
}
if (temp->coef != 0)
{
//temp->next = pc->next;
temp->next = NULL; //更直接
pc->next = temp;
pc = temp;
}
else
free(temp);
}
while (qa != NULL)
{
temp = (Poly)malloc(sizeof(Node));
temp->expn = qa->expn;
temp->coef = qa->coef;
qa = qa->next;
//temp->next = pc->next;
temp->next = NULL; //更直接
pc->next = temp;
pc = temp;
}
while (qb != NULL)
{
temp = (Poly)malloc(sizeof(Node));
temp->expn = qb->expn;
temp->coef = qb->coef;
qb = qb->next;
//temp->next = pc->next;
temp->next = NULL; //更直接
pc->next = temp;
pc = temp;
}
return headc;
}
Poly diff(Poly pa, Poly pb) //减法
{
Poly qb = pb->next;
Poly pd = NULL;
//zx 以下两句没用
//pd = (Poly)malloc(sizeof(Node));
//pd->next = NULL;
while (qb)
{
qb->coef = -qb->coef;
qb = qb->next;
}
pd = Add(pa, pb);
//zx 恢复pb中的指数
for (qb = pb->next; qb != NULL; qb = qb->next)
qb->coef *= -1;//存疑
return pd;
}
Poly Cheng(Poly pa, Poly pb)
{
Poly qa = pa->next;
Poly qb = pb->next;
Poly head, pe, temp;
Poly sum = NULL;
head = (Poly)malloc(sizeof(Node));
head->next = NULL;
//sum = (Poly)malloc(sizeof(Node));
//sum->next = NULL;
//pe->next = NULL;
//head = pe;
if (qa != NULL && qb != NULL)
{
for (qa = pa->next; qa != NULL; qa = qa->next)
{
sum = (Poly)malloc(sizeof(Node));
sum->next = NULL;
pe = sum;
for (qb = pb->next; qb != NULL; qb = qb->next)
{
temp = (Poly)malloc(sizeof(Node));
temp->coef = qa->coef * qb->coef;
temp->expn = qa->expn + qb->expn;
//temp->next = pe->next;
temp->next = NULL; //更直接
pe->next = temp;
pe = temp;
//free(temp);
//show(heade);//ERROR,此处会出现问题。使用单步调试来看，heade里面的值是乱码。程序意外终止。若注释掉本句，下一处ERROR也会发生。
//printf("qb=qb->next\n");
}
head = Add(head, sum);//ERROR，想利用整数求和的办法。sum+=a;但是总是终止。
}
//return sum;
}
//else
//{
// head->next = NULL;
// return head;
//}
return head;
}
int main()
{
Poly qc;
Poly qd;
Poly qe;
Node *p, *q;
p = Creat();
show(p);
q = Creat();
show(q);
qc = Add(p, q);
printf("加法：");
show(qc);
qd = diff(p, q);
printf("减法：");
show(qd);
qe = Cheng(p, q);
printf("乘法：");
show(qe);
return 0;
}
//请输入一个一元多项式，形如（系数c，指数e，c = 0退出）
//1, 1
//2, 2
//0, 0
//X + 2X ^ 2
//请输入一个一元多项式，形如（系数c，指数e，c = 0退出）
//2, 1
//3, 2
//0, 0
//2X + 3X ^ 2
//加法：3X + 5X ^ 2
//减法： - X - X ^ 2
//乘法：2X ^ 2 + 7X ^ 3 + 6X ^ 4
缺陷：
1.有内存泄露。
2.输入多项式时，必须按指数从小到大输入。