Reading directory content in linux

Question

How can we read the contents (subdirectories and filenames) of a directory using C language in Linux.

Answer 1

Here is a recursive program to print the name of all subdirectories and files recursively.
Usage: ./a.out path name
Error conditions are not checked for initial path name supplied as command line argument.
Basic flow of code:
All the entries in current directory are read.
if it is directory name, its name is added to path name and and function is called recursively.
else name of the files are printed.

Details about the particular functions can be referenced in respective man pages as pointed by dmuir:

#include<sys/stat.h>
#include<unistd.h>
#include<dirent.h>
#include<error.h>
int read(char *pth)
{
    char path[1000];
    strcpy(path,pth);
    DIR *dp;
    struct dirent *files;
    /*structure for storing inode numbers and files in dir
    struct dirent
    {
        ino_t d_ino;
        char d_name[NAME_MAX+1]
    }
    */
    if((dp=opendir(path))==NULL)
        perror("dir\n");
    char newp[1000];
    struct stat buf;
    while((files=readdir(dp))!=NULL)
    {
              if(!strcmp(files->d_name,".") || !strcmp(files->d_name,".."))
                continue;

        strcpy(newp,path);
        strcat(newp,"/");
        strcat(newp,files->d_name); 
            printf("%s\n",newp);

            //stat function return a structure of information about the file    
        if(stat(newp,&buf)==-1)
        perror("stat");
        if(S_ISDIR(buf.st_mode))// if directory, then add a "/" to current path
        {

            strcat(path,"/");
            strcat(path,files->d_name);
            read(path);
            strcpy(path,pth);
        }
    }
}
int main(int argc,char *argv[])
{

    read(argv[1]);
}