文件FILE写入与读取

一，介绍fgetc，fputc是一个一个字符串读取的

/*************************************************************************
> File Name:
> Author: songli
> QQ:2734030745
> Mail: 15850774503@163.com
> Created Time:
************************************************************************/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
printf("请您输入文件的路径：\n");

char filename1[50], filename2[50], ch;

scanf("%s", filename1);
FILE *in = fopen(filename1, "rb");   //以读的方式打开filename1
if (!in)
return -1;
printf("请您输入文件的路径：\n");
scanf("%s", filename2);
FILE *out = fopen(filename2, "wb");//以写的方式打开filename2
if (!out)
return -1;

while ((ch = fgetc(in)) != EOF)
{
fputc(ch, out);
printf("%c", ch);

}

fclose(in);
fclose(out);
printf("\n");
system("pause");
return EXIT_SUCCESS;
}

二，一行一行读取文件fgets和fputs

文本格式读写的

函数原型

int fgetc(FILE *stream);

char *fgets(char *s, int size, FILE *stream);

实际例子：

/*************************************************************************
> File Name:
> Author: songli
> QQ:2734030745
> Mail: 15850774503@163.com
> Created Time:
************************************************************************/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
printf("请您输入文件的路径：\n");

char filename1[50], filename2[50];
//在堆上开辟内存1kb
char *buf = (char*)malloc(sizeof(char) * 1024);
scanf("%s", filename1);
FILE *in = fopen(filename1, "rb");
if (!in)
return -1;
printf("请您输入文件的路径：\n");
scanf("%s", filename2);
FILE *out = fopen(filename2, "wb");
if (!out)
return -1;

while (!feof(in))
{
fgets(buf, sizeof(char) * 1024, in);

//写的文件中
fputs(buf, out);
}

//释放内存
free(buf);
fclose(in);
fclose(out);
printf("\n");
system("pause");
return EXIT_SUCCESS;
}

三，格式化输入和输出fscanf和fprintf的函数

函数模型

#include <stdio.h>

int scanf(const char *format, ...);
int fscanf(FILE *stream, const char *format, ...);
int sscanf(const char *str, const char *format, ...);

/*************************************************************************
> File Name:
> Author: songli
> QQ:2734030745
> Mail: 15850774503@163.com
> Created Time:
************************************************************************/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
printf("请您输入文件的路径：\n");

char filename1[50], filename2[50];

scanf("%s", filename1);
FILE *in = fopen(filename1, "rb");
if (!in)
return -1;
printf("请您输入文件的路径：\n");
scanf("%s", filename2);
FILE *out = fopen(filename2, "wb");
if (!out)
return -1;
int a, b;
char c;
while (!feof(in))
{
//这边我就简单写一下   可以用开辟堆上的内存的指针操作
fscanf(in, "%d%c%d=\n", &a, &c, &b);

printf("%d,%c，%d\n", a, c, b);

//写入一个文件中

fprintf(out, "%d%c%d=\n", a, c, b);

}

fclose(in);
fclose(out);
printf("\n");
system("pause");
return EXIT_SUCCESS;
}

效果图

四，文件随机读写好的函数fseek和ftell的使用

函数

int fseek(FILE *stream, long offset, int whence); //SEEK_SET, SEEK_CUR, SEEK_END
long ftell(FILE *stream);

void rewind(FILE *stream);

int fgetpos(FILE *stream, fpos_t *pos);
int fsetpos(FILE *stream, const fpos_t *pos);

五，文件的拷贝和切割fread和fwrite

函数的定义

#include <stdio.h>

size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);

size_t fwrite(const void *ptr, size_t size, size_t nmemb,
FILE *stream);

例子：

/*************************************************************************
> File Name:
> Author: songli
> QQ:2734030745
> Mail: 15850774503@163.com
> Created Time:
************************************************************************/
#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
printf("请您输入文件的路径：\n");

char filename1[50], filename2[50];
//在堆上开辟内存1kb
char *buf = (char*)malloc(sizeof(char) * 1024);
scanf("%s", filename1);
FILE *in = fopen(filename1, "rb");
if (!in)
return -1;
printf("请您输入文件的路径：\n");
scanf("%s", filename2);
FILE *out = fopen(filename2, "wb");
if (!out)
return -1;

while (!feof(in))
{
int len = fread(buf, sizeof(char), 1024, in);

fwrite(buf, sizeof(char), len, out);
}

//释放内存
free(buf);
fclose(in);
fclose(out);
printf("\n");
system("pause");
return EXIT_SUCCESS;
}

效果图



这里我要讲的fread函数的

的参数的返回值是读取的到数据的大小

int len = fread(buf, sizeof(char), 1024, in);

六，文件的信息的函数stat

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>

int stat(const char *pathname, struct stat *buf);
int fstat(int fd, struct stat *buf);
int lstat(const char *pathname, struct stat *buf);

#include <fcntl.h>           /* Definition of AT_* constants */

struct stat {
dev_t     st_dev;         /* ID of device contai
ning file */
ino_t     st_ino;         /* inode number */
mode_t    st_mode;        /* protection */
nlink_t   st_nlink;       /* number of hard links */
uid_t     st_uid;         /* user ID of owner */
gid_t     st_gid;         /* group ID of owner */
dev_t     st_rdev;        /* device ID (if special file) */
off_t     st_size;        /* total size, in bytes */
blksize_t st_blksize;     /* blocksize for filesystem I/O */
blkcnt_t  st_blocks;      /* number of 512B blocks allocated */

/* Since Linux 2.6, the kernel supports nanosecond
precision for the following timestamp fields.
For the details before Linux 2.6, see NOTES. */

struct timespec st_atim;  /* time of last access */
struct timespec st_mtim;  /* time of last modification */
struct timespec st_ctim;  /* time of last status change */

#define st_atime st_atim.tv_sec      /* Backward compatibility */
#define st_mtime st_mtim.tv_sec
#define st_ctime st_ctim.tv_sec
};

还有几个还是没有讲到 分别是重置文件光标位置：

rewind(文件指针)

文件属性：

1、导入头文件 sys/types.h sys/stat.h

2、定义文件状态结构体 struct stat st

3、获取文件状态 stat(文件名，&st)

4、获取文件大小st.st_size

删除：

remove(路径+文件名)成功返回值为0

重命名（移动）：

rename(路径+老文件名，路径+新文件名)成功返回值为0

更新文件缓冲区：

fflush(文件指针)