readFileInDir.cpp

#include <dirent.h>

vector<string> readFileInDir(char* path_to_image) {
    vector<string> paths;
    DIR* dp=opendir(path_to_image);
    string s_path_to_image = path_to_image;

    if (dp!=NULL)
    {
        struct dirent* d;
        do{
            d = readdir(dp);
            if (d!=NULL) {
                string file_name = d->d_name;
                paths.push_back(s_path_to_image + file_name);
            }
        }while(d!=NULL);
    }
    closedir(dp);

    return paths;
}

path[0]とpath[1]には，"your_path/."と"your_path/.."が入る( どの環境でも？ )