数据结构一元多项式c++加减

以下是一元多项式的C++加减代码示例：

#include<iostream>
using namespace std;

struct node{
    int coef,exp;
    node *next;
};

node *create(int n){
    node *head,*p,*q;
    head=new node;
    head->next=NULL;
    q=head;
    for(int i=1;i<=n;i++){
        p=new node;
        cin>>p->coef>>p->exp;
        p->next=NULL;
        q->next=p;
        q=p;    }
    return head;
}

node *add(node *a,node *b){
    node *head,*p,*q,*r;
    head=new node;
    head->next=NULL;
    p=a->next;
    q=b->next;
    r=head;
    while(p!=NULL&&q!=NULL){
        if(p->exp<q->exp){
            r->next=p;
            r=p;
            p=p->next;
        }
        else if(p->exp>q->exp){
            r->next=q;
            r=q;
            q=q->next;
        }
        else{
            if(p->coef+q->coef!=0){
                p->coef+=q->coef;
                r->next=p;
                r=p;
            }
            p=p->next;
            q=q->next;
        }
    }
    if(p!=NULL) r->next=p;
    if(q!=NULL) r->next=q;
    return head;
}

node *sub(node *a,node *b){
    node *head,*p,*q,*r;
    head=new node;
    head->next=NULL;
    p=a->next;
    q=b->next;
    r=head;
    while(p!=NULL&&q!=NULL){
        if(p->exp<q->exp){
            r->next=p;
            r=p;
            p=p->next;
        }
        else if(p->exp>q->exp){
            q->coef=-q->coef;
            r->next=q;
            r=q;
            q=q->next;
        }
        else{
            if(p->coef-q->coef!=0){
                p->coef-=q->coef;
                r->next=p;
                r=p;
            }
            p=p->next;
            q=q->next;
        }
    }
    while(p!=NULL){
        r->next=p;
        r=p;
        p=p->next;
    }
    while(q!=NULL){
        q->coef=-q->coef;
        r->next=q;
        r=q;
        q=q->next;
    }
    return head;
}

void print(node *head){
    node *p;
    p=head->next;
    while(p!=NULL){
        cout<<p->coef<<" "<<p->exp<<endl;
        p=p->next;
    }
}

int main(){
    int n,m;
    node *a,*b,*c,*d;
    cin>>n>>m;
    a=create(n);
    b=create(m);
    c=add(a,b);
    d=sub(a,b);
    print(c);
    print(d);
    return 0;
}