IT company 100 question-12-calculate 1 + 2 +... + N

Problem description:

1 + 2 +... + N. the keyword such as multiplication and division, for, while, if, else, switch, and Case and the condition judgment statement (? B: C ). Analysis: Use static variables of the class to implement:If new contains N arrays of this type, the constructor of this class will be called N times. Code implementation:

 1 // 12.cc 2 #include <iostream> 3 using namespace std; 4  5 class Object { 6 public: 7     Object() { 8         ++N; 9         Sum += N;10     }11     static void reset() { N = 0; Sum = 0; }12     static int get_sum() { return Sum; }13 14 private:15     static int N;16     static int Sum;17 };18 19 int Object::N = 0;20 int Object::Sum = 0;21 22 int sum(int n) {23     Object::reset();24 25     Object* a = new Object[n];26 27     delete []a;28     a = 0;29 30     return Object::get_sum();31 }32 33 int main() {34     int n = 10;35     cout << "The sum is: " << sum(n) << endl;36     return 0;37 }