C语言链表的问题

Insert函数里编的有点乱,其他的没看。
struct student* insert(struct student *head,struct student *stu)
{
struct student *p1,*p2;
p1=NUll; p2=head;
while(p2!=NULL&&stu->num>p2->num){
p1=p2;
p2=p2->next;
}
if(p1==NULL) head=stu;
else p1->next=stu;
stu->next=p2;
retuen head;
}

前两天作为作业，我也编了一个学生动态链表，供你参考。程序在VC++2005上编译、运行通过，链表部分使用的是标准算法。

//by 兔弟蛇哥

#include
#include
#include
#include

#define NL printf("\n");
#define CLS system("CLS");
#define PAUSE system("PAUSE");
#define EMPTYLINE while(getchar()!='\n');

#define MAX_STDUENT_NUM 50 //当前允许的最大学生数以及允许的最大学号

struct student{
int number;
char name[50];
float mark[4]; //分别表示语文、数学、英语、总分
struct student *next;
};
struct student *Head;
int StudentNum;
struct student *Head_Orderly[4];

void GO(int);
void PrintStu(struct student *);
struct student* Creat(struct student*);
void SearchOrderly(int,struct student *,struct student **,struct student**);
int SeachStdNum(int,struct student *);
float InputNum(char *,int,int,char *);
int InputYN(void);
struct student* SearchStuByName(char [],struct student *);
struct student* SearchStuByNum(int,struct student *);
int DeleteByNum(int,struct student **);
int DeleteByName(char [],struct student **);
struct student *BeOrdered(struct student *,int);

void main()
{
Head=NULL;
StudentNum=0; //已输入的学生总数
int k,choice;
for(k=0;k<4;k++)
Head_Orderly[k]=NULL;

while(1){
printf("**********学生成绩动态链表示意程序**********\n\n");
printf("当前设定的最大学生数：%d\n",MAX_STDUENT_NUM);
printf("当前设定的学号范围：1-%d\n",MAX_STDUENT_NUM);
printf("1 输入新的学生数据\n");
printf("2 删除指定学生数据\n");
printf("3 查询学生成绩信息\n");
printf("0 退出\n");
NL NL

choice=(int)InputNum("请选择：",0,3,"int");
GO(choice);
}
}

void GO(int choice){

struct student *T,*p;
int number,choice2,choice3;
char name[50];
switch(choice){
case 0: exit(EXIT_SUCCESS);
case 1: {Head=Creat(Head); break;}
case 2: {NL NL
if(Head==NULL){
printf("很遗憾，链表中没有学生！\n");
return;
}

printf("1 按姓名\n");
printf("2 按学号\n");
printf("3 返回\n");
NL NL
choice2=(int)InputNum("请选择：",1,3,"int");
switch(choice2){
case 3: return;
case 1: {printf("请输入要删除的学生姓名：");
scanf("%s",name);
DeleteByName(name,&Head);
break;
}
case 2: {
number=(int)InputNum("请输入要删除的学生学号：",1,MAX_STDUENT_NUM,"int");
DeleteByNum(number,&Head);
break;
}
}
break;
}
case 3: {NL NL
if(Head==NULL){
printf("很遗憾，链表中没有学生！\n");
return;
}

printf("1 查询全部\n");
printf("2 按姓名查询\n");
printf("3 按学号查询\n");
printf("4 按语文分数排序\n");
printf("5 按数学分数排序\n");
printf("6 按英语分数排序\n");
printf("7 按总分分数排序\n");
printf("8 返回\n");
NL NL
choice3=(int)InputNum("请选择：",1,8,"int");
if(choice3==8) return;
if(choice3==1) {PrintStu(Head); return;}
if(choice3==2){printf("请输入要查询的学生姓名：");
scanf("%s",name);
p=SearchStuByName(name,Head);

if(p==NULL)
printf("无此学生！\n\n");
else{
T=(struct student*)malloc(sizeof(struct student));
*T=*p;
T->next=NULL;
PrintStu(T);
}
return;
}
if(choice3==3){
number=(int)InputNum("请输入要查询的学生学号：",1,MAX_STDUENT_NUM,"int");
p=SearchStuByNum(number,Head);
if(p==NULL)
printf("无此学生！\n\n");
else{
T=(struct student*)malloc(sizeof(struct student));
*T=*p;
T->next=NULL;
PrintStu(T);
}
return;
}
Head_Orderly[choice3-4]=BeOrdered(Head,choice3-4);
PrintStu(Head_Orderly[choice3-4]);
return;
}
}
}

void PrintStu(struct student *head)
{
struct student *p;
int i=0;
p=head;
printf("序号\t学号\t姓名\t语文\t数学\t英语\t总分\n");
while(p!=NULL){
printf("%d\t%d\t%s\t%.1f\t%.1f\t%.1f\t%.1f\n",++i,p->number,&p->name,p->mark[0],p->mark[1],p->mark[2],p->mark[3]);
p=p->next;
}
NL NL
PAUSE
NL NL
return;
}

struct student* Creat(struct student *head) //新建或插入链表
{
struct student *p,*u,*v; //p：新建表元指针；v，u：查询时的当前表元和前驱表元的指针
p=u=v=NULL;

/*创建新表元*/
while(1){
if(StudentNum==MAX_STDUENT_NUM){
printf("学生已输满！\n\n");
return head;
}

p=(struct student*)malloc(sizeof(struct student));
while(1){
p->number=(int)InputNum("学号:",1,MAX_STDUENT_NUM,"int");
if(head==NULL||SeachStdNum(p->number,head)==0) break;//检查学号是否重复（允许不顺序输入学号）
printf("学号重复！请重输：");
}

printf("请输入姓名:");
scanf("%s",p->name);
p->mark[0]=InputNum("语文成绩:",0,100,"float");
p->mark[1]=InputNum("数学成绩:",0,100,"float");
p->mark[2]=InputNum("英语成绩:",0,100,"float");
p->mark[3]=p->mark[0]+p->mark[1]+p->mark[2];
p->next=NULL;

/*按学号顺序插入新表元*/
if(head==NULL) head=p;
else{
SearchOrderly(p->number,head,&v,&u);
if(v==NULL) head=p;
else v->next=p;
p->next=u;
}
StudentNum++;
printf("添加成功！现有学生：%d人。\n",StudentNum);
printf("是否继续(Y/N)?");
if(InputYN()==0) return head;
}
}

void SearchOrderly(int num,struct student *head,struct student **v,struct student **u)
{
struct student *u1,*v1;
v1=NULL;
u1=head;
while(u1!=NULL&&num>u1->number){
v1=u1;
u1=u1->next;
}
*v=v1;
*u=u1;
return;
}

int SeachStdNum(int num,struct student *head)
{
struct student *p;
p=head;
while(p!=NULL&&p->number!=num)
p=p->next;
if(p==NULL) return 0;
else return 1;
}

float InputNum(char *string,int range_min,int range_max,char *mode)
{
char temp[10];
int i;
int err;
char mode1[]="int";
union{
int a;
float b;
}input;
for(;;){
err=0;
printf("%s",string);
scanf("%10s",temp);
EMPTYLINE
if(strlen(temp)>4) continue;
for(i=0;temp[i]!='\0';i++)
if((isdigit(temp[i])==0&&temp[i]!='.')||(isdigit(temp[i])==0&&strcmp(mode1,mode)==0)) err=1;
if(err) continue;
if(strcmp(mode1,mode)==0){
input.a=atoi(temp);
if(input.a>=range_min&&input.a<=range_max)
return (float)input.a;
}
else{
input.b=atof(temp);
if(input.b>=(float)range_min&&input.b<=(float)range_max)
return input.b;

}
}
}

int InputYN() //检查输入。（N(n)或Y(y)）
{
char t[3];
while(1){
scanf("%2s",&t);
EMPTYLINE
if(t[1]) printf("输入的字符过多！");
else if(t[0]=='Y'||t[0]=='y') return 1;
else if(t[0]=='N'||t[0]=='n') return 0;
else printf("输入有误！");
NL
printf("请重新输入：");
}
}

struct student* SearchStuByName(char name[],struct student *head)
{
struct student *p;
p=head;
while(p!=NULL){
if(strcmp(name,p->name)==0) return p;
p=p->next;
}
return NULL;
}

struct student* SearchStuByNum(int Num,struct student *head)
{
struct student *p;
p=head;
while(p!=NULL){
if(p->number==Num) return p;
p=p->next;
}
return NULL;
}

int DeleteByNum(int Num,struct student **head)
{
struct student *v,*u;
u=v=NULL;
SearchOrderly(Num,*head,&v,&u);
if(u==NULL||u->number!=Num){
printf("找不到此学号的学生！删除失败。");
NL NL
return 1;
}
if(v==NULL) *head=u->next;
else v=u->next;
u->next=NULL;
free(u);
StudentNum--;
printf("删除成功！现在链表中共有%d位学生。",StudentNum);
NL NL
return 0;
}

int DeleteByName(char name[],struct student **head)
{
struct student *v,*u;
v=NULL;
u=*head;
while(u!=NULL&&strcmp(u->name,name)){
v=u;
u=u->next;
}
if(u==NULL){
printf("找不到此姓名的学生！删除失败。");
NL NL
return 1;
}
if(v==NULL) *head=u->next;
else v=u->next;
u->next=NULL;
free(u);
StudentNum--;
printf("删除成功！现在链表中共有%d位学生。",StudentNum);
NL NL
return 0;
}

struct student *BeOrdered(struct student *head,int mode)
{

struct student *newhead,*p,*newp,*u,*v,*u2;
int i;
p=head;
newhead=u=v=NULL;

while(p!=NULL){
newp=(struct student*)malloc(sizeof(struct student));
*newp=*p;
newp->next=NULL;

if(newhead==NULL) newhead=newp;
else{
v=NULL; u=newhead;
while(u!=NULL&&newp->mark[mode]mark[mode]){
v=u;
u2=u;
u=u->next;
}
if(newp->mark[mode]==u2->mark[mode]){ //如果该科成绩相等，依次以语文、数学、英语的顺序排序
for(i=0;i<3;i++){
if(newp->mark[mode]>u->mark[mode]){
v=u;
u=u->next;
break;
}
}
}

if(v==NULL) newhead=newp;
else v->next=newp;
newp->next=u;
}
p=p->next;
}
return newhead;
}

花了将近一个小时,终于搞好了.在机上试过,可以通过VC++6.0
好累啊.终于弄好了.是时候要睡觉了.
#include
#include
struct student //你的这个程序没有结束的控制机制
{
long num;
float chengji;
struct student *next;
};
int n; //n 应该用来控制输入的次数
struct student * creat();
void output(struct student *head);
struct student* del(struct student *head,long num);
struct student* insert(struct student *head,struct student *stu);

void main()
{ int temp=0;
long num;
struct student *head=NULL,*stud=NULL; //这样改进一下更加的完美
printf("please input how many links do you want:");
scanf("%d",&n);
do{
printf("press 1 to initialize the link \n 2 to display the link \n 3 to delect the link \n 4 to insert the link \n0 to exit\n");
scanf("%d",&temp);
stud=NULL;
switch(temp)
{case 1: printf("请输入链表：");
head=creat();
output(head);
break;
case 2: output(head);break;
case 3: printf("请输入要删除的链表:");
scanf("%ld",&num);
head=del(head,num);
output(head); break;
case 4:
printf("请输入要插入的链表:");
scanf("%ld,%f",&stud->num,&stud->chengji);
head=insert(head,stud);
scanf("%ld,%f",&stud->num,&stud->chengji);
output(head);
break;

default: break;}
} while(temp!=0);

}

struct student* creat()
{
struct student *head,*p1,*p2;
int i=0; //此处引入一个i,用以计数,控制创建表的个数,程序应改成如下:

head=p1=p2=(student*)malloc(sizeof(student));
scanf("%ld,%f",&p1->num,&p1->chengji);
if(n==1) {p1->next=NULL;}
else

while(p1!=NULL&&i {

p1=(student*)malloc(sizeof(student));
scanf("%ld,%f",&p1->num,&p1->chengji);
p2->next=p1;
p2=p1;
i++;
}
p2->next=NULL;
return(head);
}
void output(struct student *head)
{
struct student *p;
printf("链表为：\n");
p=head;
if(head!=NULL)
{
while(p!=NULL) //此处用while,请不要用do...while 否则会算多一次
{ printf("%ld,%f\n",p->num,p->chengji);
p=p->next; }

}
}

struct student* del(struct student *head,long num)
{
struct student *p1,*p2;
if(head==NULL) printf("没有链表！\n");
p1=head;
while(num!=p1->num&&p1->next!=NULL)
{ p2=p1;
p1=p1->next;
}
if(num==p1->num)
{
if(p1==head) head=p1->next;
else
{ p2->next=p1->next; }
printf("删除了%ld链表\n",num);
n--;
}
else
printf("找不到该链表！");
return(head);
}
struct student* insert(struct student *head,struct student *stu)
{
struct student *p1,*p2,*p3;
p1=head;
p2=stu;
if(head==NULL)
{ head=p2;
p2->next=NULL; }
else
{
while((p2->num>p1->num)&&(p1->next!=NULL))
{
p3=p1;
p1=p1->next;
}
if(p2->num<=p1->num)
{
if(head==p1)
{ head=p2; }
else
{ p3->next=p2; }
p2->next=p1;
}
else
{
p1->next=p2;p2->next=NULL;
}
}
n=n+1;
return(head);
}