C 语言 文件操作

程序中有时候，我们需要生成多个文件名连续的文件，那么我们就需要用到函数

sprintf, swprintf

int sprintf( char *buffer, const char *format [, argument] ... );

int swprintf( wchar_t *buffer, const wchar_t *format [, argument] ... );

Routine	Required Header	Compatibility
sprintf	<stdio.h>	ANSI, Win 95, Win NT
swprintf	<stdio.h> or <wchar.h>	ANSI, Win 95, Win NT

Libraries

LIBC.LIB	Single thread static library, retail version
LIBCMT.LIB	Multithread static library, retail version
MSVCRT.LIB	Import library for MSVCRT.DLL, retail version

Return Value

sprintf returns the number of bytes stored in buffer, not counting the terminating null character. swprintf returns the number of wide characters stored in buffer, not counting the terminating null wide character.

Parameters

buffer

Storage location for output

format

Format-control string

argument

Optional arguments

 /*批量生成文件名为 Beauty01.txt,Beauty02.txt,Beauty03.txt......

  内容写文件名 */

#include<stdio.h>

#include<stdlib.h>

 

int main()

{

 

   unsigned char file_name[15];

 

   unsigned i;

  

   for(i=1;i<=9;i++)

   {

      sprintf(file_name,"Beauty%02d.txt",i);

      freopen(file_name,"wb",stdout);

      printf("%s\n",file_name);

   }

  

   return 0;

}

 

程序中有时候，我们需要生成多个文件名连续的文件，那么我们就需要用到函数 

sprintf, swprintf

int sprintf( char *buffer, const char *format [, argument] ... );

int swprintf( wchar_t *buffer, const wchar_t *format [, argument] ... );

Routine	Required Header	Compatibility
sprintf	<stdio.h>	ANSI, Win 95, Win NT
swprintf	<stdio.h> or <wchar.h>	ANSI, Win 95, Win NT

Libraries

LIBC.LIB	Single thread static library, retail version
LIBCMT.LIB	Multithread static library, retail version
MSVCRT.LIB	Import library for MSVCRT.DLL, retail version

Return Value

sprintf returns the number of bytes stored in buffer, not counting the terminating null character. swprintf returns the number of wide characters stored in buffer, not counting the terminating null wide character.

Parameters

buffer

Storage location for output

format

Format-control string

argument

Optional arguments

 

 

 

 

/*批量生成文件名为 Beauty01.txt,Beauty02.txt,Beauty03.txt......

  内容写文件名

 */

#include<stdio.h>

#include<stdlib.h>

 

int main()

{

 

   unsigned char file_name[15];

 

   unsigned i;

  

   for(i=1;i<=9;i++)

   {

      sprintf(file_name,"Beauty%02d.txt",i);

      freopen(file_name,"wb",stdout);

      printf("%s\n",file_name);

   }

  

   return 0;

}

 

读取文本信息，并且以追加的方式写入

#include<stdio.h>

#include<stdlib.h>

 

void isOpenFile(FILE *fp)

{

    if(NULL == fp) //打开文件失败

    {

       printf("\nError Open the File!\n");

      

       getch();

      

       exit(1);

    }

    return;

}

 

int main()

{

    FILE *my_file;

   

    my_file    = fopen("G:\\cpp\\test.txt","rb");

   

    isOpenFile(my_file);

   

    char ch;

    ch = fgetc(my_file);

   

    while((0 == feof(my_file)))

    {

       putchar(ch);

       ch = fgetc(my_file);

    }

   

    fclose(my_file); //关闭文件

   

    /************************************************/

   

    my_file = fopen("G:\\cpp\\test.txt","ab+");

   

    isOpenFile(my_file);

   

    int i;

   

    for(i=0;i<100;i++)

    {

       fputc(i,my_file);

    }

    rewind(my_file);

   

    ch = fgetc(my_file);

   

    while((0 == feof(my_file)))

    {

       printf("%d ",ch);

       ch = fgetc(my_file);

    }

    fclose(my_file);

    /*************************************************/

    putchar(-43);   //test

    putchar(-30);

    return 0;

}

 

如何获得未知文件的大小

fseek

Moves the file pointer to a specified location.

int fseek( FILE *stream, long offset, int origin );

orgin：

SEEK_CUR

Current position of file pointer

SEEK_END

End of file

SEEK_SET

Beginning of file

ftell

Gets the current position of a file pointer.

long ftell( FILE *stream );

Code：

#include<stdio.h>

#include<stdlib.h>

 

void isOpenFile(FILE *fp)

{

    if(NULL == fp) //打开文件失败

    {

       printf("\nError Open the File!\n");

      

       getch();

      

       exit(1);

    }

    return;

}

 

int main()

{

    FILE *my_file;

   

    my_file    = fopen("G:\\cpp\\test.txt","rb");

   

    isOpenFile(my_file);

   

    fseek(my_file,0,SEEK_END);

   

    int Length = ftell(my_file);

    rewind(my_file);

    printf("%d\n",Length);

   

fclose(my_file);     

return 0;

}