这为啥运行结果是空的啊，编译也没问题

Question

 
#include <stdio.h>
#include <stdlib.h>
struct space{
        int xishu;
        int zhishu;
        struct space *next;
};
struct space* create();
void print(struct space *p);
struct space* mul(struct space *p1,struct space *p2);
struct space* add(struct space *p1,struct space *p2);
void attach(int c,int e,struct space **L2);
int main(){
    struct space *p1;
    struct space *p2;
    struct space *p3;
    struct space *p4;
    p1 = create();
    p2 = create();
    p3 = mul(p1,p2);
    p4 = add(p1,p2);
    print(p3);
    print(p4);
    return 0;
}
struct space* create(){ //创建链表 
    int n,i;
    scanf("%d",&n);
    struct space *head;
    struct space *rom;
    rom=(struct space*)malloc(sizeof(struct space));
    head=rom;
    while(n--){
    rom=rom->next;
    rom=(struct space*)malloc(sizeof(struct space));
    scanf("%d %d",&rom->xishu,&rom->zhishu);
    }
    rom->next=NULL;
    return head;
}
struct space* mul(struct space *p1,struct space *p2){ //两个多项式相乘 
    struct space *L,*front1,*middle1,*middle2;
    L=(struct space*)malloc(sizeof(struct space));
    L->next=NULL;
    front1=L;
    p1=p1->next;
    p2=p2->next;
    middle1=p1;
    L=L->next;
    for(;middle1;middle1=middle1->next){
        middle2=p2;
        for(;middle2;middle2=middle2->next){
    L->xishu=(middle1->xishu)+(middle2->xishu);
    L->zhishu=(middle1->zhishu)*(middle2->zhishu);
    L->next = NULL;
    L=L->next;
    L=(struct space*)malloc(sizeof(struct space));
    L->next = NULL;
        }
    }
    return front1;
}
struct space* add(struct space *p1,struct space *p2){ //两个多项式相加 
    struct space *L2,*front2;
    L2=(struct space*)malloc(sizeof(struct space));
    L2->next=NULL;
    front2=L2;
    p1=p1->next;
    p2=p2->next;
    while(p1&&p2){
    if(p1->zhishu>p2->zhishu){
        attach(p1->xishu,p1->zhishu,&L2);
        p1=p1->next;
    }else if(p2->zhishu>p2->zhishu){
        attach(p2->xishu,p2->zhishu,&L2);
        p2=p2->next;
    }else{
        if(p2->xishu+p1->xishu){
            attach(p1->xishu+p2->xishu,p1->zhishu,&L2);
            p2=p2->next;
            p1=p1->next;
        }else{
            ;
        }
    }
}
        L2->next=p1?p1:p2;
        return front2;
}
void attach(int c,int e,struct space **L2){ //将系数、指数插到新链表里 
    struct space *p;
    p=(struct space*)malloc(sizeof(struct space));
    p->ishu=c;
    p->zhishu=e;
    (*L2)->next=p;
    (*L2)=p;
}
void print(struct space *p){ //打印 
    p=p->next;
    while(p){
        printf("%d %d",p->xishu,p->zhishu);
        if(p->next){
        printf(" ");
        }
        p=p->next;
    }
}
 

Answer 1

```c

//代码太多了，眼会花，先改这个创建的函数，改完还有错就继续来
struct space* create(){ //创建链表 
    int n,i;
    scanf("%d",&n);
    struct space *head;
    struct space *rom;
    head=(struct space*)malloc(sizeof(struct space));
    rom=head;
    while(n--){
    rom->next=(struct space*)malloc(sizeof(struct space));
    rom=rom->next;
    scanf("%d %d",&rom->xishu,&rom->zhishu);
    }
    rom->next=NULL;
    return head;
}

```