问题描述

新手上路，链表学习中，问题是对功能函数不理解，问题已备注，请帮我在问题处写思路，尤其功能函数，谢谢！

//第九章章末习题第10题
#include//建立a b两链表包含学号成绩，把两个链表合并升序排列输出。求思路！
#include
#define LEN sizeof(struct student)

struct student
{
long num;
int score;

struct student * next;

};
struct student listalistb;
int nsum=0;

int main()
{
struct student * creat(void);//创建链表函数
struct student * insert(struct student struct student *);//合并排序函数
void print(struct student *);//输出函数
struct student * ahead * bhead abh;
printf(""input list a:n"");
ahead = creat();
sum = sum + n;//此语句不理解，请兄台解释下
printf(""input list b:n"");
bhead = creat();
sum = sum + n;//此语句不理解
abh = insert(aheadbhead);
print(abh);
return 0;
}

struct student creat(void)
{
struct student * p1 p2* head;
n = 0;
p1 = p2 = (struct student * )malloc(LEN);
printf(""input number && score of student:n"");
printf(""if number is 0please stop inputing:n"");
scanf(""%ld%d""&p1->num&p1->score);
head=NULL;
while(p1->num != 0)
{
n = n+1;
if(n == 1)
head = p1;
else
p2->next = p1;
p2=p1;
p1 = (struct student *)malloc(LEN);
scanf(""%ld%d""&p1->num&p1->score);
}
p2->next = NULL;
return (head);
}
//建立insert函数用来合并两个链表

struct student * insert(struct student * ahstruct student * bh)//问题就是//这个功能函数直接不理解{    struct student * pa1* pa2* pb1* pb2;    pa2 = pa1 = ah;//此处不理解    pb2 = pb1 = bh;//此处不理解    do    {while((pb1->num > pa1->num) && (pa1->next != NULL))    {        pa2 = pa1;        pa1 = pa1->next;    }//此处不理解    if(pb1->num <= pa1->num)    {        if(ah == pa1)            ah = pb1;        else            pa2->next = pb1;        pb1 = pb1->next;        pb2->next = pa1;        pa2 = pb2;        pb2 = pb1;    }//此处不理解    }    while((pa1->next != NULL)||(pa1 == NULL) && (pb1 != NULL));    if((pb1 != NULL) && (pb1->num > pa1->num) && (pa1->next == NULL))        pa1->next = pb1;//此处不理解    return (ah);}//输出函数void print(struct student * head){    struct student * p;    printf(""There are %d records:n""sum);    p = head;    if(p != NULL)        do        {            printf(""%ld%dn""p->nump->score);            p = p->next;        }        while(p != NULL);}

解决方案

我建议楼主看看老谭的《C程序设计》第三版，里面对链表的各项操作讲的很清晰的，下面是前三版中将链表插入的操作，希望对楼主有帮助。
struct student *insert(struct student *head struct student *stud)
{ struct student *p0*p1*p2;
p1=head;
p0=stud;
if(head==NULL) {head=p0; p0->next=NULL;}
else{while((p0->num>p1->num) && (p1->next!=NULL))
{p2=p1; p1=p1->next;}
if(p0->num<=p1->num)

{ if(head==p1) head=p0;
else p2->next=p0; p0->next=p1;}
else {p1->next=p0; p0->next=NULL;}}
n=n+1;

return(head);
}