这代码写完，我差不多就已经不认识了。
题目：写一个图书管理程序，要求可以增加记录，读取记录，删除记录，修改记录。我从11点半写到1点半，然后越写越觉得这代码写的可真蠢。
程序代码：#include <stdio.h>
#include <stdlib.h>
typedef struct {
char title[50];
char author[50];
float value;
int del_tag;
}BOOKS;
void menu(void);
void f_read(void);
void data_add(void);
void data_delete(void);
FILE * f_open(void);
void f_write(BOOKS a[], int arrays);
long int datas = 0;
int main(void)
{
typedef void(*P_FUN)(void);
P_FUN fun_M[3] = { f_read,data_delete,data_add };
int option = 0;
FILE *p_file;
p_file = f_open();
fclose(p_file);
while (menu(), scanf("%d", &option) == 1)
{
if (option >= 3)
printf("该选项不存在\n");
else if (option < 0)
printf("该选项不存在\n");
else if (!datas && option != 2)
printf("文件中没有记录。\n");
else
fun_M[option]();
}
return 0;
}
void menu(void)
{
printf("0) 读取文件\n");
printf("1) 删除/修改记录\n");
printf("2) 增加记录\n");
printf("q) 退出\n");
}
void f_read(void)
{
FILE * p_file;
long int data_in = 0;
int st_size = sizeof(BOOKS);
BOOKS book;
p_file = f_open();
for (data_in = 0; data_in < datas; data_in += st_size)
{
fseek(p_file, data_in, SEEK_SET);
fread(&book, sizeof(BOOKS), 1, p_file);
printf("%-25s %s ￥%.2f\n", book.title, book.author, book.value);
}
fseek(p_file, 0, SEEK_END);
datas = ftell(p_file);
fclose(p_file);
}
void data_add(void)
{
BOOKS a;
FILE * p_file;
p_file = f_open();
while (getchar() != '\n');
while (printf("输入书名（空行结束）："), gets(a.title) != NULL && a.title[0] != '\0')
{
while (printf("输入作者："), gets(a.author) == NULL || a.author[0] == '\0');
printf("输入单价：");
scanf("%f", &a.value);
a.del_tag = 1;
while (getchar() != '\n');
fwrite(&a, sizeof(BOOKS), 1, p_file);
}
fseek(p_file, 0, SEEK_END);
datas = ftell(p_file);
fclose(p_file);
}
void data_delete(void)
{
int arrays = datas / sizeof(BOOKS);
BOOKS a[arrays];
int n, array_in;
FILE * p_file;
p_file = f_open();
for (n = 0, array_in = 0; n < datas && array_in < arrays; array_in++, n += sizeof(BOOKS))
{
fseek(p_file, n, SEEK_SET);
fread(&a[array_in], sizeof(BOOKS), 1, p_file);
}
fclose(p_file);
while (printf("0.删除\n1.修改\n2.返回主菜单\n"), scanf("%d", &n) == 1 && n != 2)
{
if (!n)
{
for (array_in = 0; array_in < arrays; array_in++)
printf("%d %s %s: %.2f\n", array_in, a[array_in].title, a[array_in].author, a[array_in].value);
while (printf("输入要删除的记录的编号,可选范围0-%d(q退出):", arrays - 1), scanf("%d", &array_in) == 1)
{
if (array_in > arrays)
printf("记录不存在.\n");
else if (!a[array_in].del_tag)
printf("记录不存在.\n");
else
a[array_in].del_tag = 0;
}
while (getchar() != '\n');
}
else if (n == 1)
{
for (array_in = 0; array_in < arrays; array_in++)
printf("%d %s %s: %.2f\n", array_in, a[array_in].title, a[array_in].author, a[array_in].value);
while (printf("输入要修改的记录的编号,可选范围0-%d(q退出):", arrays - 1), scanf("%d", &array_in) == 1)
{
if (array_in > arrays)
printf("记录不存在\n");
else if (!a[array_in].del_tag)
printf("该记录已经被删除\n");
else
{
while (getchar() != '\n');
while (printf("输入新的书名："), gets(a[array_in].title) == NULL || a[array_in].title[0] == '\0');
while (printf("输入新的作者名："), gets(a[array_in].author) == NULL || a[array_in].author[0] == '\0');
printf("输入新的价格：");
scanf("%f", &a[array_in].value);
}
}
while (getchar() != '\n');
}
}
f_write(a, arrays);
}
FILE * f_open(void)
{
FILE *p_file;
if ((p_file = fopen("books_s.dat", "a+b")) == NULL)
{
fprintf(stderr, "无法打开文件");
exit(EXIT_FAILURE);
}
fseek(p_file, 0, SEEK_END);
datas = ftell(p_file);
return p_file;
}
void f_write(BOOKS a[], int arrays)
{
FILE * p_file;
int array_in;
if ((p_file = fopen("books_s.dat", "w+b")) == NULL)
{
fprintf(stderr, "无法打开文件");
exit(EXIT_FAILURE);
}
for (array_in = 0; array_in < arrays; array_in++)
if (a[array_in].del_tag)
fwrite(&a[array_in], sizeof(BOOKS), 1, p_file);
datas = ftell(p_file);
fclose(p_file);
}
[此贴子已经被作者于2017-1-31 15:20编辑过]
