#include <iostream>
#include <opencv2/core.hpp>
#include <sys/stat.h>

using namespace std;
using namespace cv;

inline bool file_exists (const std::string& name) {
  struct stat buffer;   
  return (stat (name.c_str(), &buffer) == 0); 
}
  
int main(int argc, char** argv)
{
    string input;
    
    if (argc == 2) {
        input = argv[1];
    } else if (argc < 2) {
        cerr << "Please provide one image." << endl;
        return -1;
    } else if (argc > 2) {
        cerr << "Please provide only one image." << endl;
        return -2;
    }

    if (!file_exists(input)) {
        cerr << "File " << input << " does not exist." << endl;
        return -3;
    }

    cout << "Using image " << input << "." << endl;
  
    return 0;
}