main.cpp

一元多项式乘法 包含密运算 新学数据结构的可以参考参考

#include <iostream>

using namespace std;

struct Poly                  //定义一个线性表存储多项式
{
    int coef;
    int exp;
    struct Poly *next;
};
typedef struct Poly  Poly;

Poly *creatPoly()   ;
Poly *Polyadd(Poly *newpoly,int coef,int exp);
Poly *PolyMultiplication (Poly * polya, Poly * polyb);
void Polyprint(Poly *mul);


int main()
{
    Poly *polya,*polyb,*mul;
    printf("Please input the first Polynomial:\n");
    polya=creatPoly();
    printf("Please input the second Polynomial:\n");
    polyb=creatPoly();
    mul=PolyMultiplication(polya,polyb);
    printf("The results of the polynomial are:\n");
    Polyprint(polya);
    printf(" * ");
    Polyprint(polyb);
    printf(" = ");
    Polyprint(mul);

}

Poly *creatPoly()               //创建新的多项式
{
    Poly *head,*rear,*s;
    int c,e;

    head=new Poly;
    rear=head;
    scanf("%d%d",&c,&e);
    while (c!=0)
    {
        s=new Poly;
        s->coef=c;
        s->exp=e;
        rear->next=s;
        rear=s;
        scanf("%d%d",&c,&e);
    }
    rear->next=NULL;
    return head;
}


Poly *Polyadd(Poly *newpoly,int coef,int exp)        //多项式相加 每个线性表与其下一个线性表相加
{
    Poly *p=newpoly->next;

    Poly *l=newpoly;

    while (p!=NULL)
    {
        if (p->exp<exp)
        {
            l=p;
            p=p->next;
        }
        else if (p->exp==exp)
        {
            p->coef+=coef;
            {
                if (p->coef==0)
                {
                    p=p->next;
                    delete l->next;
                    l->next=p;
                }
                return newpoly;
            }

        }
        else
        {
            l->next=new Poly;
            l->next->next=p;
            p=l->next;
            p->coef=coef;
            p->exp=exp;

            return newpoly;
        }
    }

    l->next=new Poly;
    p=l->next;
    p->coef=coef;
    p->exp=exp;
    p->next=NULL;
    return newpoly;
}

Poly * PolyMultiplication (Poly * polya, Poly * polyb)  //多项式相乘
{
    int coef, exp;
    Poly * newpoly = new Poly ;
    newpoly-> next = NULL ;
    for ( Poly * f = polya->next ; f!= NULL ;f = f -> next)     //多项式的循环相乘
        for ( Poly * s = polyb->next ; s != NULL; s = s -> next)
        {
            coef =(f-> coef )*(s-> coef);
            exp = f->exp + s->exp ;
            newpoly= Polyadd(newpoly,coef, exp );              //多项式与前一个多项式相加
        }
    return newpoly;
}

void Polyprint(Poly *mul)   //打印多项式结果
{
    Poly *p=mul->next;

    while (p!=NULL)
    {
        if (!((p->coef==1||p->coef==-1)&&p->exp!=0))
            printf("%d",p->coef);
        if (p->exp!=0)
            printf("x");
        if (p->exp!=1&&p->exp!=0)
            printf("(%d)",p->exp);
        if (p->next!=NULL&&p->next->coef>0)
            printf("+");
        if (p->next!=NULL&&p->next->coef<0)
            printf("-");a
        p=p->next;
    }
}