Linux/unix reads all the file names under the specified directory __linux

Linux/unix reads all file names under the specified directory call the system function Opendir () and readdir to traverse all the files under a specified directory under Linux/unix and output the file name. The implementation code is as follows:

*
	author:acb0y
	FileName:main.cpp
	Create time:2011 August 1 0:41:18
	version:v1.0
 * * *
#include <iostream>
#include "apue.h"
#include <dirent.h>
using namespace std;

int main (int argc, char * argv[])
{
	DIR *dp;
	struct dirent *dirp;
	if (argc!= 2) 
	{
		err_quit ("Usage:ls directory_name");
	
	Opens the specified directory
	if ((DP = Opendir (argv[1])) = = NULL)
	{
		Err_sys ("can ' t open%s", argv[1]);
	}
	
	Traverse Directory
	while ((DIRP = Readdir (DP))!= NULL)
	{
		printf ("%s\n", dirp->d_name);
	}
	
	Close Directory
	Closedir (DP);
	return 0;
}