想问一下，这个程序在编译的时候都没错误的，为什么在输入完计算的时候却出错了了呢？希望有人可以帮一下忙，谢谢啦先
#include<iostream.h>
#include<stdlib.h>
struct Polynomail{
    float coef;
    int expn;
    struct Polynomail*next;
};
void CreatNode(Polynomail *p, float a, int b){
    struct Polynomail *q=new struct Polynomail;
    q->coef=a;
    q->expn=b;
    p->next=q;
}
void CreatPolynomail(Polynomail *p,int m){
    struct Polynomail *p1;
    p1=p;
    float a;
    int b;
    int i;
    for(i=1;i<=m;i++){
        cout<<"请输入第"<<i<<"项的系数和次数"<<endl;
        cin>>a>>b;
        if(b<=p1->expn){cout<<"输入有误";exit(0);}
        CreatNode(p1,a, b);
        p1=p1->next;
    }
    p1=p1->next;
}
void PrintPolynomail(Polynomail *p){
    struct Polynomail *p1;
    p1=p->next;
    if(p1->expn==0)cout<<p1->coef;
    else cout<<p1->coef<<"x^"<<p1->expn;
    p1=p1->next;
    while(p1!=NULL){
        if(p1->coef<=0) cout<<p1->coef<<"x^"<<p1->expn;
        else cout<<"+"<<p1->coef<<"x^"<<p1->expn;
        p1=p1->next;
    }
}
int CMPare(int a, int b){
    if(a<b)return -1;
    if(a==b)return 0;
    if(a>b)return 1;
}
void AddPolynomail(Polynomail *pa, Polynomail *pb){
    struct Polynomail *ha, *hb, *p1, *p2;
    p1=ha=pa;
    p2=hb=pb;
    struct Polynomail *qa=ha->next;
    struct Polynomail *qb=hb->next;
    int a,b;
    float sum;
    while(qa&&qb){
        a=qa->expn;
        b=qb->expn;
        switch(CMPare(a,b)){
        case -1:p1=qa;qa=qa->next; break;
        case 0 :sum=qa->coef+qb->coef;
            if(sum!=0.0){qa->coef=sum; p1=qa;qa=qa->next;}
            else{p1->next=qa->next;delete pa;qa=p1->next;}
            p2->next=qb->next;delete qb; qb=p2->next; break;
        case 1 :p2->next=qb->next; p1->next=qb;qb->next=qa;qb=p2->next;p1=p1->next;break;
        }
    }
    if(qb!=NULL)p1->next=qb;
    delete hb;
}
void MultPolynomail(Polynomail *pc, Polynomail *pa, Polynomail *pb){
    pc->next=NULL;
    struct Polynomail *p1, *p2, *p3, *q;
    p2=pb->next;
    while(p2!=NULL){
        p1=pa->next;
        struct Polynomail *p4=new struct Polynomail;
        p3=p4;
        while(p1!=NULL){
            q=new struct Polynomail;
            q->coef=p1->coef*p2->coef;
            q->expn=p1->expn+p2->expn;
            p3->next=q;
            p3=p3->next;
            p1=p1->next;
        }
        p3->next=NULL;
        AddPolynomail(pc,p4);
        p2=p2->next;
    }
}
int main(){
    int fa, fb;
    struct Polynomail *pa=new struct Polynomail; pa->expn=-1;
    struct Polynomail *pb=new struct Polynomail; pb->expn=-1;
    cout<<"请输入多项式f的项数"<<endl;
    cin>>fa;
    CreatPolynomail(pa, fa);
    cout<<"请输入多项式g的项数"<<endl;
    cin>>fb;
    CreatPolynomail(pb, fb);
    cout<<"f(x)=";
    PrintPolynomail(pa);
    cout<<endl;
    cout<<"g(x)=";
    PrintPolynomail(pb);
    cout<<endl;
    struct Polynomail *pc=new struct Polynomail; pc->expn=-1;
    MultPolynomail(pc, pa, pb );
    cout<<"f(x)*g(x)=";
    PrintPolynomail(pc);
    cout<<endl;
    AddPolynomail(pa, pb);
    cout<<"f(x)+g(x)=";
    PrintPolynomail(pa);
    cout<<endl;
    return 0;
}

答非所问[em20]