? cv::imwrite(image_name, vec_test_images[i]);
?}

?//train images and train labels
?//read MNIST image into OpenCV Mat vector
?string filename_train_images = "D:/Download/train-images-idx3-ubyte/train-images.idx3-ubyte";
?int number_of_train_images = 60000;
?vector vec_train_images;

?read_Mnist(filename_train_images, vec_train_images);

?//read MNIST label into int vector
?string filename_train_labels = "D:/Download/train-labels-idx1-ubyte/train-labels.idx1-ubyte";
?vector vec_train_labels(number_of_train_images);

?read_Mnist_Label(filename_train_labels, vec_train_labels);

?if (vec_train_images.size() != vec_train_labels.size()) {
? cout<<"parse MNIST train file error"<? return -1;
?}

?//save train images
?for (int i = 0; i < 10; i++)
? count_digits[i] = 0;

?string save_train_images_path = "D:/Download/MNIST/train_images/";

?for (int i = 0; i < vec_train_images.size(); i++) {
? int number = vec_train_labels[i];
? string image_name = GetImageName(number, count_digits);
? image_name = save_train_images_path + image_name + ".jpg";

? cv::imwrite(image_name, vec_train_images[i]);
?}

?return 0;
}