c - 如何使我的程序按大小或上次修改时间排序？- C

Question

#include<stdio.h>
#include<unistd.h>
#include<fcntl.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<dirent.h>
#include<stdlib.h>
#include<dirent.h>
#include<string.h>
#include<pwd.h>
#include<grp.h>

#define BUFFERSIZE      4096
#define COPYMODE        0644


void cpMain(char *, char *);
void ls2Main(int, char *);
void oops(char *, char *);
void do_ls(char[]);
void dostat(char *);
void show_file_info( char *, struct stat *);
void mode_to_letters( int , char [] );
char *uid_to_name( uid_t );
char *gid_to_name( gid_t );

int main(int argc, char *argv[])
{   
if(argc == 1)
{
    char s1[20];
    char s2[20];    
        cpMain(s1,s2);
    int lsVar = 1;
    char lsArg[20] = "/home";
    ls2Main(lsVar, lsArg);
}
}

void cpMain(char *argv, char *argv2)
{   
char s1[20];
char s2[20];
printf("Enter source.\n");
scanf("%s", s1);
printf("Enter destination.\n");
scanf("%s", s2);
    int     in_fd, out_fd, n_chars;
    char    buf[BUFFERSIZE];



    if ( (in_fd=open(s1, O_RDONLY)) == -1 )
            oops("Cannot open ", s1);

    if ( (out_fd=creat(s2, COPYMODE)) == -1 )
            oops( "Cannot creat", s2);


    while ( (n_chars = read(in_fd , buf, BUFFERSIZE)) > 0 )
            if ( write( out_fd, buf, n_chars ) != n_chars )
                    oops("Write error to ", s2);
if ( n_chars == -1 )
        oops("Read error from ", s1);



    if ( close(in_fd) == -1 || close(out_fd) == -1 )
            oops("Error closing files","");

}

void ls2Main(int ac, char *av)
{
if ( ac == 1 )
    do_ls( "." );
return;
}

void oops(char *s1, char *s2)
{   
    fprintf(stderr,"Error: %s ", s1);
    perror(s2);
    exit(1);
}
void do_ls( char dirname[] )
{
DIR     *dir_ptr;       
struct dirent   *direntp;       

if ( ( dir_ptr = opendir( dirname ) ) == NULL )
    fprintf(stderr,"ls2: cannot open %s\n", dirname);
else
{
    while ( ( direntp = readdir( dir_ptr ) ) != NULL ) {
        if (strcmp(direntp->d_name,".")==0 ||
            strcmp(direntp->d_name,"..")==0) continue;
        dostat( direntp->d_name );
    }
    closedir(dir_ptr);
}
}


void dostat( char *filename )
{
struct stat info;

if ( stat(filename, &info) == -1 )      
    perror( filename );     
else                    
    show_file_info( filename, &info );
}


void show_file_info( char *filename, struct stat *info_p )

{
char    *uid_to_name(), *ctime(), *gid_to_name(), *filemode();
void    mode_to_letters();
    char    modestr[11];

mode_to_letters( info_p->st_mode, modestr );

printf( "%s"    , modestr );
printf( "%4d "  , (int) info_p->st_nlink);  
printf( "%-8s " , uid_to_name(info_p->st_uid) );
printf( "%-8s " , gid_to_name(info_p->st_gid) );
printf( "%8ld " , (long)info_p->st_size);
printf( "%.12s ", 4+ctime(&info_p->st_mtime));
printf( "%s\n"  , filename );

}



void mode_to_letters( int mode, char str[] )
{
strcpy( str, "----------" );           

if ( S_ISDIR(mode) )  str[0] = 'd';    
if ( S_ISCHR(mode) )  str[0] = 'c';    
if ( S_ISBLK(mode) )  str[0] = 'b';    

if ( mode & S_IRUSR ) str[1] = 'r';    
if ( mode & S_IWUSR ) str[2] = 'w';
if ( mode & S_IXUSR ) str[3] = 'x';

if ( mode & S_IRGRP ) str[4] = 'r';    
if ( mode & S_IWGRP ) str[5] = 'w';
if ( mode & S_IXGRP ) str[6] = 'x';

if ( mode & S_IROTH ) str[7] = 'r';    
if ( mode & S_IWOTH ) str[8] = 'w';
if ( mode & S_IXOTH ) str[9] = 'x';
}


char *uid_to_name( uid_t uid )

{
struct  passwd *getpwuid(), *pw_ptr;
static  char numstr[10];

if ( ( pw_ptr = getpwuid( uid ) ) == NULL ){
    sprintf(numstr,"%d", uid);
    return numstr;
}
else
    return pw_ptr->pw_name ;
}


char *gid_to_name( gid_t gid )

{
struct group *getgrgid(), *grp_ptr;
static  char numstr[10];

if ( ( grp_ptr = getgrgid(gid) ) == NULL ){
    sprintf(numstr,"%d", gid);
    return numstr;
}
else
    return grp_ptr->gr_name;
}

我上面的代码首先运行 cp 命令，然后输出与ls -l在终端中输入相同的内容。我试图弄清楚如何使ls零件按大小（好像您要键入ls -lS）或上次修改时间（如果您要键入ls -lt）对输出进行排序，但我正在努力弄清楚如何做到这一点。谁能帮我弄清楚该怎么做？

标签： c