📄 00000003.htm
字号:
<HTML><HEAD> <TITLE>BBS水木清华站∶精华区</TITLE></HEAD><BODY><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER>发信人: xcec (money), 信区: Linux <BR>标 题: guest-->datafile.h, datafile.cpp <BR>发信站: BBS 水木清华站 (Mon Jan 17 13:06:50 2000) WWW-POST <BR> <BR>//datafile.h
<BR>#ifndef DATAFILE_H
<BR>#define DATAFILE_H
<BR>
<BR>#define MAX_ENTRY 1000
<BR>#define INDEX_FILE "index"
<BR>#define DATA_FILE "data"
<BR>
<BR>#define NAME_LENGTH 10
<BR>#define MAIL_LENGTH 20
<BR>#define HOMEPAGE_LENGTH 30
<BR>#define TITLE_LENGTH 100
<BR>#define CONTENT_LENGTH 2000
<BR>#define IP_LENGTH 16
<BR>#define TIME_LENGTH 30
<BR>
<BR>struct GUEST {
<BR> char name[NAME_LENGTH];
<BR> char mail[MAIL_LENGTH];
<BR> char homepage[HOMEPAGE_LENGTH];
<BR> char title[TITLE_LENGTH];
<BR> char content[CONTENT_LENGTH];
<BR> char ip[IP_LENGTH];
<BR> char time[TIME_LENGTH];
<BR>};
<BR>
<BR>class DATAFILE {
<BR> int tail;
<BR> int add[MAX_ENTRY];
<BR> int link[MAX_ENTRY];
<BR>public:
<BR> DATAFILE();
<BR> ~DATAFILE();
<BR> GUEST *read(GUEST *, int);
<BR> GUEST *write(GUEST *);
<BR> int del_record(int);
<BR> int get_record_num(void);
<BR>};
<BR>
<BR>#endif
<BR>
<BR>//datafile.cpp
<BR>#include <stdio.h>
<BR>#include "datafile.h"
<BR>
<BR>DATAFILE::DATAFILE()
<BR>{
<BR> FILE *file;
<BR> if ( !(file = fopen(INDEX_FILE, "rb")) ) {
<BR> tail = 0;
<BR> for (int i = 0; i < MAX_ENTRY; i++) {
<BR> add[i] = -1;
<BR> link[i] = 0;
<BR> }
<BR> }
<BR> else {
<BR> fread(this, sizeof(DATAFILE), 1, file);
<BR> fclose(file);
<BR> }
<BR>}
<BR>
<BR>DATAFILE::~DATAFILE()
<BR>{
<BR> FILE *file;
<BR> file = fopen(INDEX_FILE, "wb");
<BR> fwrite(this, sizeof(DATAFILE), 1, file);
<BR> fclose(file);
<BR>}
<BR>
<BR>GUEST *DATAFILE::read(GUEST *guest, int n)
<BR>{
<BR> if (n <= 0 || n > tail)
<BR> return NULL;
<BR>
<BR> FILE *file;
<BR> if ( !(file = fopen(DATA_FILE, "rb")) )
<BR> return NULL;
<BR>
<BR> int size = sizeof(GUEST);
<BR> fseek(file, add[n-1]*size, 0);
<BR> fread(guest, size, 1, file);
<BR>
<BR> fclose(file);
<BR> return guest;
<BR>}
<BR>
<BR>GUEST *DATAFILE::write(GUEST *guest)
<BR>{
<BR> if (tail >= MAX_ENTRY)
<BR> return NULL;
<BR>
<BR> int i = 0;
<BR> while (link[i])
<BR> ++i;
<BR> link[i] = 1;
<BR> add[tail++] = i;
<BR>
<BR> FILE *file;
<BR>
<BR> if ( !(file = fopen(DATA_FILE, "r+b")) ) {
<BR> file = fopen(DATA_FILE, "ab");
<BR> fclose(file);
<BR> file = fopen(DATA_FILE, "r+b");
<BR> }
<BR> fseek(file, i*sizeof(GUEST), 0);
<BR> fwrite(guest, sizeof(GUEST), 1, file);
<BR> fclose(file);
<BR>
<BR> return guest;
<BR>}
<BR>
<BR>int DATAFILE::del_record(int n)
<BR>{
<BR> if (n < 1 || n > tail)
<BR> return 0;
<BR> link[add[n-1]] = 0;
<BR> int i = n-1;
<BR> while (i < tail - 1) {
<BR> add[i] = add[i + 1];
<BR> i++;
<BR> }
<BR> add[--tail] = -1;
<BR> return n;
<BR>}
<BR>
<BR>int DATAFILE::get_record_num(void)
<BR>{
<BR> return tail;
<BR>} <BR> <BR>-- <BR>※ 来源:·BBS 水木清华站 smth.org·[FROM: 162.105.33.162] <BR><CENTER><H1>BBS水木清华站∶精华区</H1></CENTER></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -