前辈帮忙指导，里面的程序有些问题想请教
程序代码：
#include <stdio.h>
#include <stdlib.h>
struct sdu_info{
int number; //学号
int sex; //0为男，1为女
int age; //年龄
int class; //班级代码
int counter; //成绩分数
struct sdu_info * next; //节点指针
};
typedef struct sdu_info Sdu; //Sdu链表
typedef Sdu * SduPtr; //Sdu链表指针
int input(int i);
void set(int i,SduPtr *head,SduPtr *last);
void add(SduPtr *head,SduPtr *last);
void List(SduPtr head);
//以下的函数可否用函数指针来处理，请前辈指教
SduPtr chake(int data,int i,SduPtr head,SduPtr last);
SduPtr ck01(int data,SduPtr head,SduPtr last);
SduPtr ck02(int data,SduPtr head,SduPtr last);
SduPtr ck03(int data,SduPtr head,SduPtr last);
SduPtr ck04(int data,SduPtr head,SduPtr last);
SduPtr ck05(int data,SduPtr head,SduPtr last);
//以下函数有问题。
void del(SduPtr *head,SduPtr *last);
int main(int argc, char **argv)
{
SduPtr head = NULL; //头元素地址
SduPtr last = NULL; //最后元素地址
int i = 0; //流程控制码
do {
// printf("in main head = %p , last = %p\n",head,last);
set(input(i),&head,&last);
List(head);
}while(1);
return 0;
}
//输入增加、删除操作码
int input(int i){
printf("1 is add , 2 is del , input your select : ");
do {
scanf("%d",&i);
}while(i!=1 && i!=2);
return i;
}
//接收操作码后的操作
void set(int i,SduPtr *head,SduPtr *last){
switch (i){
case 1:
add(head,last);
break;
case 2:
del(head,last);
break;
default:
printf("select error !\n");
break;
}
}
//实现添加链表
void add(SduPtr *head,SduPtr *last){
SduPtr p = (SduPtr)malloc(sizeof(Sdu));
//申请失败则提示并返回
if ( p == NULL){
printf("malloc cache is NULL , error!\n");
return;
}
//申请成功,录入新数据
printf("input your mouber :");
scanf("%d",&p->number);
printf("input sex (0 man , 1 wuman):");
scanf("%d",&p->sex);
printf("input your age :");
scanf("%d",&p->age);
printf("input your class :");
scanf("%d",&p->class);
printf("input counter :");
scanf("%d",&p->counter);
//每次都从head重新计算last的地址
*last = *head;
//插入新数据p
if (*head == NULL){ //表空的操作
*head = p;
*last = p;
(*head)->next = NULL;
}else{ //表不为空的操作
if ((*head)->next == NULL){ //表不空，但只有表头1个数据的操作
(*head)->next = p;
*last = p;
(*last)->next = NULL;
}else{
do { //很多数据，则重新计算生成last的地址并链接新数据
*last = (*last)->next;
}while((*last)->next != NULL);
(*last)->next = p;
*last = p;
}
}
// printf("in add head = %p , last = %p , p = %p\n",*head,*last,p);
}
//按选择的类型与其值来搜索删除数据
void del(SduPtr *head,SduPtr *last){
SduPtr p , now1 , now2 ;
int i , data;
//数据为null返回
if (*head == NULL){
printf("link node is NULL, no data .\n");
return ;
}
//否则操作录入要删除的资料
printf("1 del number , 2 del sex , 3 del age , 4 del class ,5 del counter .\n");
printf("input your del type num : ");
scanf("%d",&i);
printf("input your del data value : ");
scanf("%d",&data);
//检查是否存在要删除的数组，有则接收其指针p，无则NULL
p = chake(data,i,*head,*last);
//操作查询返回的结果p
now1 = *head;
now2 = *head;
if (p == NULL){
printf("no your find DATA , error !\n");
}else{
if(now1->next == NULL){
*head = NULL;
}else{
do {
now2 = now2->next;
if (now2 == p){
now1->next = now2->next;
free(now2);
break;
}
now1 = now2;
}while(now2->next != NULL);
}
}
}
SduPtr chake(int data,int i,SduPtr head,SduPtr last){
SduPtr p;
switch (i){
case 1:
p = ck01(data,head,last);
break;
case 2:
p = ck02(data,head,last);
break;
case 3:
p = ck03(data,head,last);
break;
case 4:
p = ck04(data,head,last);
break;
case 5:
p = ck05(data,head,last);
break;
}
return p;
}
SduPtr ck01(int data,SduPtr head,SduPtr last){
SduPtr i = head;
do {
if (i->number == data){
break;
}
i = i->next;
}while(i->next != NULL);
if (i == last){
i = NULL;
}
return i;
}
SduPtr ck02(int data,SduPtr head,SduPtr last){
SduPtr i = head;
do {
if (i->sex == data){
break;
}
i = i->next;
}while(i->next != NULL);
if (i == last){
i = NULL;
}
return i;
}
SduPtr ck03(int data,SduPtr head,SduPtr last){
SduPtr i = head;
do {
if (i->age == data){
break;
}
i = i->next;
}while(i->next != NULL);
if (i == last){
i = NULL;
}
return i;
}
SduPtr ck04(int data,SduPtr head,SduPtr last){
SduPtr i = head;
do {
if (i->class == data){
break;
}
i = i->next;
}while(i->next != NULL);
if (i == last){
i = NULL;
}
return i;
}
SduPtr ck05(int data,SduPtr head,SduPtr last){
SduPtr i = head;
do {
if (i->counter == data){
break;
}
i = i->next;
}while(i->next != NULL);
if (i == last){
i = NULL;
}
return i;
}
void List(SduPtr head){
SduPtr i = head;
if (i == NULL){
printf("now is NULL\n");
}else{
do{
printf("data ptr = %p , ",i);
printf(
"number %d,sex %d,age %d,class %d,counter %d.\n",
i->number,i->sex,i->age,i->class,i->counter);
i = i->next;
printf("\n");
}while(i != NULL);
}
}
