read_image.cpp

#include <queue>
#include <iostream>
#include <opencv2/opencv.hpp>
#include "dirent.h"

using namespace std;
using namespace cv;

int main(int, char** argv)
{
	setlocale(LC_ALL, "");

	DIR *dir = opendir(argv[1]);
	dirent *ent = NULL;
	queue<DIR *> dir_que;
	dir_que.push(dir);

READ_IMAGE:
	if (dir_que.size() == 0)
	{
		cout << "all files readed done!" << endl;
		return 0;
	}

	dir = dir_que.front();
	if (dir == NULL || (ent = readdir(dir)) == NULL)
	{
		if (dir)
			closedir(dir);
		dir_que.pop();
		goto READ_IMAGE;
	}

	char dir_path[MAX_PATH];
	size_t ret;
	dirent_wcstombs_s(&ret, dir_path, PATH_MAX, dir->wdirp->patt, PATH_MAX);
	dir_path[ret - 2] = '\0';
	string path = dir_path;
	path = path + "/" + ent->d_name;

	if (ent->d_type == DT_DIR && strcmp(ent->d_name, ".") && strcmp(ent->d_name, ".."))
	{
		dir_que.push(opendir(path.c_str()));
		goto READ_IMAGE;
	}
	else if (ent->d_type != DT_REG || (strstr(ent->d_name, ".jpg") == NULL))
		goto READ_IMAGE;

PROCESS_IMAGE:
	Mat img = imread(path);
	/* more processing */
	
	/* read next image */
	goto READ_IMAGE;
	return 0;
}