Create C++ version

cpp/include/chicken_counter/capture.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stdexcept>
+#include <string>
+
+#include <opencv2/videoio.hpp>
+
+namespace cc {
+
+inline cv::VideoCapture open_capture(const std::string& source) {
+    cv::VideoCapture cap;
+    if (source.size() == 1 && std::isdigit(source[0])) {
+        cap.open(std::stoi(source));
+    } else {
+        cap.open(source);
+    }
+    if (!cap.isOpened())
+        throw std::runtime_error("Unable to open video source: " + source);
+    return cap;
+}
+
+} // namespace cc