Linux under C programming-----io/file operation simulation Linux LS program display file system tree structure (2)

The io/file operation exercises under Linux, although the knowledge is simple but often the foundation is easy to overlook, the occasional practice is necessary.

Practice printf

/*************************************************************************> File name:printf.c> Author: > Mail: > Created time:wed 01:08:15 AM PST **************************************************************** /#include <stdio.h>int main () {     printf ("%10s\n", "Hello");    printf ("%-10s\n", "Hello");    printf ("%s\n", "Hello");    printf ("%*s\n", "Ten," "Hello");    printf ("%010d\n", +);    printf ("%10.4g\n", 1.22);    printf ("%10s\n", "Hello,i am a programmer!");    return 0;}

Practice C Standard library File replication is faster than system calls because there is buffering

/*************************************************************************> File name:cpy.c> Author: > Mail: > Created time:wed 01:37:56 AM PST **************************************************************** /#include <stdio.h>int main () {       int c;    File*in=fopen ("./printf", "R");    File*out=fopen ("./printf_tem", "w");    while ((C=fgetc ())!=eof)    {        FPUTC (c,out);    }    Exit (0);}

Practice Viewing the status of a file

/*************************************************************************> File name:fileinfo.c> Author: > Mail: > Created time:wed 11:25:21 PM PST ************************************************************ /#include <stdio.h> #include <sys/stat.h> #include <unistd.h> int main () {    int Fileno ;   struct  stat filestat;   File*pfile= fopen ("./cpy", "R");   if (pfile==null)    {        printf ("File Open error!\n");        Exit (0);    }   fileno= Fileno (pFile);   printf ("filenumber:%d\n", Fileno);  if ( -1==fstat (fileno,&filestat))    {        printf ("GetFileInfo error!\n");        Exit (0);    }    printf ("deviceid:%d\n", Filestat.st_dev);    printf ("userid:%d\n", filestat.st_uid);    printf ("groupid:%d\n", filestat.st_gid);    printf ("filesize:%d\n", filestat.st_size);    return 0;}

we simulate the LS program under Linux

/*************************************************************************> File name:listdir.c> Author: > Mail: > Created time:thu 12:49:13 AM PST ************************************************************ /#include <stdio.h> #include <unistd.h> #include <sys/stat.h> #include <dirent.h> #include <string.h> #include <sys/types.h>void list_func (char*path,int depth) {dir*pdirhandle= Opendir (PA    TH);    struct dirent * dent;    struct stat fstat;        if (pdirhandle==null) {printf ("Opendir%s error!\n", path);    Exit (0);    } chdir (path);        while ((Dent=readdir (Pdirhandle))!=null) {//error then return-1 lstat (Dent->d_name,&fstat);            if (S_isdir (Fstat.st_mode)) {//remove director. and.              if (strcmp (".", Dent->d_name) ==0| |            strcmp ("..", Dent->d_name) ==0) continue; printf ("%*s%s/\n", Depth, "", DENT-&GT;d_name);        List_func (DENT-&GT;D_NAME,DEPTH+4);             }else printf ("%*s%s\n", Depth, "", dent->d_name);    } chdir (".."); Closedir (Pdirhandle);}        int main (int argc,char**argv) {if (argc<2) {printf ("Param format:listdir path\n");    return;    } Char*pdirpath=argv[1];    int depath=0;    printf ("List begin:\n");    List_func (Pdirpath,depath);    printf ("List end.\n"); return 0;}

Linux under C programming-----io/file operation simulation Linux LS program display file system tree structure (2)