added a comment

src/main.cu

@@ -10,6 +10,7 @@ int main() {
     std::string variable = "U";
     auto x = readData(path, variable);
 
+    // Print some values from the file to see that it worked
     int num = 0;
     for(int i = 0; i < x.size(); i++) {
         if (x[i] < 1E14) std::cout << x[i] << "\n";