程式碼：

#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <stdio.h>
#include <iostream>
#include <string>
#include <vector>

using namespace std;

void ScanDir(const std::string path, std::vector<std::string> &files)
{
    DIR    *dir;
    struct    dirent    *ptr;
    dir = opendir(path.c_str()); ///open the dir

    while((ptr = readdir(dir)) != NULL) ///read the list of this dir
    {
        files.push_back(ptr->d_name);
    }
    closedir(dir);
}

void PrintFiles(const vector<std::string> &files)
{
    cout << "當前目錄下有" << files.size() << "個檔案,它們是:" << endl;
	
    for(auto i = files.cbegin(); i != files.cend(); ++i)
    {
        cout << *i << endl;
    }
}

int main(int argc, char **argv)
{
    std::string path;
    std::vector<std::string> files;
	
    if(argc >= 2)
    {
        path = std::string(argv[1]);
    }
    else
    {
        path = std::string("./");
    }
	
    ScanDir(path, files);
    PrintFiles(files);
    
    return 0;
}