Need help with this c++ program

Write a postincrement++operator that changes an EvenNumber to the next even number (add two to its value). The operator is declared in the class, you need to implement it after the class declaration. Code: 1 #include 2 using namespace std; 5 class EvenNumber { 6 public: explicit EvenNumber (int n) 4 value = (n % 2--0) ? n : n - 1; //must be even 10 EvenNumber operator++(int dummy)i 12 13 14 15 16 private: 17 18 19 20 //Do not modify anything on or above the line below this 21 YOUR CODE BELOW int getValue) const return value; int value; 23 //YOUR CODE 24 25 //yOUR CODE ABOVE 26 //Do not modify anything on or below the line above this 27 28 29 int main() 31 EvenNumber nl(6) //print its curent value, then increment cout