能不能简单解释一下这里的函数、指针的用法（结构体中）是不是利用指针把菜单引在....
#include <stdio.h>#include <stdlib.h>
#include <malloc.h>
#include<windows.h> // Sleep函数
#define LEN sizeof(struct student) // student结构的大小
void Commands_menu(void);
struct student *Create(struct student *head);
struct student *Insert(struct student *head, struct student *stu_2);
struct student *Del(struct student *head);
void Print(struct student *head);
void Quit(void);
void SlowDisplay(char *p);
struct student
{
int num;
float score;
struct student *next;
};
int n=0; // 链表节点数
int choose_number; // 命令选择指向默认
int is_num; // 检查输入是否为数字
char proof; // 判断 Y/N
int main()
{
SlowDisplay("\n\t学 生 成 绩 管 理 系 统\n");
Commands_menu();
return 0;
}
//*******************************命令菜单*******************************
void Commands_menu(void)
{
struct student *head=NULL, stu_2;
while (1)
{
puts("\n************************************************************************");
printf("****\t1 : 创建数据\t< 友情提醒: 执行'创建数据'命令会覆盖旧数据库! >\n");
printf("****\t2 : 插入数据\n");
printf("****\t3 : 删除数据\n");
printf("****\t4 : 打印数据\n");
printf("****\t0 : 退出!\n");
puts("************************************************************************");
SlowDisplay("\n请输入执行命令 : ");
choose_number = 9;
switch(scanf("%d", &choose_number), choose_number)
{
case 1:
// 一次过滤所有非法字符输入
while(getchar() != '\n')
{
;
}
SlowDisplay("\n确定创建新数据库, 覆盖旧数据库? < Y / N > : ");
proof = getchar();
if(proof == 'y' || proof == 'Y')
{
SlowDisplay("\n数据库重建中...\t< 学号、成绩输入 '0' 则退出! >\n");
head = Create(head);
}
else if(proof == 'n' || proof == 'N')
{
SlowDisplay("\n取消创建! 继续!\n");
}
else
{
SlowDisplay("\n创建失败! 输入非法!\n");
}
Print(head);
break;
case 2:
head = Insert(head, &stu_2);
Print(head);
break;
case 3:
head = Del(head);
Print(head);
break;
case 4:
Print(head);
break;
case 0:
Quit();
break;
default:
SlowDisplay("\n输入非法!\n\n");
}
// 一次过滤所有非法字符输入
while(getchar() != '\n')
{
;
}
}
}
//*******************************创建数据*******************************
struct student *Create(struct student *head)
{
struct student *p1, *p2;
n = 0;
head = NULL;
p1 = p2 = (struct student *)malloc(LEN);
printf("\n\t录入第 %d 位学生学号 : ", n+1);
// 检查非法输入
while(!(is_num = scanf("%d", &p1->num)))
{
printf("\n\t请重新输入学生学号(纯数字) : ");
while(getchar() != '\n')
{
;
}
}
if(p1->num == 0)
{
SlowDisplay("\n结束创建!\n");
return head;
}
printf("\n\t录入第 %d 位学生成绩 : ", n+1);
// 检查非法输入
while(!(is_num = scanf("%f", &p1->score)) || p1->score < 0 || p1->score >100)
{
printf("\n\t请重新输入学生成绩(0~100的数字) : ");
while(getchar() != '\n')
{
;
}
}
while (p1->num)
{
n++;
if (1 == n)
{
head = p1;
}
else
{
p2->next = p1;
}
p2 = p1;
p1 = (struct student *)malloc(LEN);
getchar();
printf("\n\t请继续录入第 %d 位学生学号 : ", n+1);
// 检查非法输入
while(!(is_num = scanf("%d", &p1->num)))
{
printf("\n\t请重新输入学生学号(纯数字) : ");
while(getchar() != '\n')
{
;
}
}
if(p1->num == 0)
{
SlowDisplay("\n结束创建!\n");
p2->next = NULL;
return head;
}
printf("\n\t请继续录入第 %d 位学生成绩 : ", n+1);
// 检查非法输入
while(!(is_num = scanf("%f", &p1->score)) || p1->score < 0 || p1->score >100)
{
printf("\n\t请重新输入学生成绩(0~100的数字) : ");
while(getchar() != '\n')
{
;
}
}
}
p2->next = NULL;
SlowDisplay("\n创建成功!\n");
return head;
}
//*******************************插入数据*******************************
struct student *Insert(struct student *head, struct student *stu_2)
{
struct student *p1, *p2;
stu_2 = (struct student *)malloc(LEN);
printf("\n请录入要插入学生学号(输入'0'取消) : ");
// 检查非法输入
while(!(is_num = scanf("%d", &stu_2->num)))
{
printf("\n\t请重新输入学生学号(纯数字) : ");
while(getchar() != '\n')
{
;
}
}
if(stu_2->num == 0)
{
SlowDisplay("\n取消插入!\n");
return head;
}
printf("\n请录入要插入学生成绩 : ");
// 检查非法输入
while(!(is_num = scanf("%f", &stu_2->score)) || stu_2->score < 0 || stu_2->score > 100)
{
printf("\n\t请重新输入学生成绩(0~100的数字) : ");
while(getchar() != '\n')
{
;
}
}
p1 = head;
if(head == NULL)
{
head = stu_2;
stu_2->next = NULL;
}
else
{
while (p1->next != NULL && stu_2->num > p1->num)
{
p2 = p1;
p1 = p1->next;
}
if (stu_2->num <= p1->num)
{
if (head == p1)
{
head = stu_2;
}
else
{
p2->next = stu_2;
}
stu_2->next = p1;
}
else
{
p1->next = stu_2;
stu_2->next = NULL;
}
}
n++;
SlowDisplay("\n插入成功!");
printf("\n插入学号 : %d\n", stu_2->num);
return head;
}
//*******************************删除数据*******************************
struct student *Del(struct student *head)
{
struct student *p1, *p2;
int num;
getchar();
printf("\n请输入您想删除的学生学号(输入'0'取消) : ");
// 检查非法输入
while(!(is_num = scanf("%d", &num)))
{
printf("\n\t请重新输入学生学号(纯数字) : ");
while(getchar() != '\n')
{
;
}
}
if(num == 0)
{
SlowDisplay("\n取消删除!\n");
return head;
}
p1 = head;
if(head == NULL)
{
SlowDisplay("\n删除失败!");
printf("\n数据库为空!\n");
}
else
{
while (p1->next != NULL && num != p1->num)
{
p2 = p1;
p1 = p1->next;
}
if (num == p1->num)
{
if (p1 == head)
{
head = p1->next;
}
else
{
p2->next = p1->next;
}
SlowDisplay("\n删除成功!");
printf("\n删除学号 : %d\n", num);
n--;
}
else
{
SlowDisplay("\n删除失败!");
printf("\n无匹配学号 : %d\n", num);
}
}
return head;
}
//*******************************打印数据*******************************
void Print(struct student *head)
{
struct student *p;
SlowDisplay("\n数据库打印中...");
puts("\n************************************************************************");
printf("\n****\t数据库中共计有 %d 条记录!\n", n);
p = head;
while (p)
{
printf("\n\t学号 : %d , 成绩 : %5.2f", p->num, p->score);
p = p->next;
}
putchar('\n');
}
//*******************************退出*******************************
void Quit(void)
{
// 一次过滤所有非法字符输入
while(getchar() != '\n')
{
;
}
SlowDisplay("\n确定退出? < Y / N > : ");
proof = getchar();
if(proof == 'y' || proof == 'Y')
{
SlowDisplay("\n数据库保存中...\n");
// 执行数据库保存...
SlowDisplay("\n * * * *\n");
SlowDisplay("\n * * * *\n");
SlowDisplay("\n * * * *\n");
SlowDisplay("\n数据库已保存, 系统退出!\t");
exit(0);
}
else if(proof == 'n' || proof == 'N')
{
SlowDisplay("\n取消退出! 继续!\n");
}
else
{
SlowDisplay("\n输入非法! 继续!\n");
}
}
//*******************************慢显*******************************
void SlowDisplay(char *p)
{
while(1)
{
if(*p!=0)
printf("%c",*p++);
else
break;
Sleep(50);
}
} 你这代码真长
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