#includeIn this example, we create a QVariantMap called `map` and insert three key-value pairs into it. We then use the `size()` function to determine the number of key-value pairs in the map and store it in the variable `size`. The Qt library provides the implementation of QVariantMap.int main() { QVariantMap map; map.insert("name", "John"); map.insert("age", 30); map.insert("isMarried", true); int size = map.size(); // returns the number of key-value pairs in the map (in this case, 3) return 0; }