~~~ #include <iostream> #include <string> using namespace std; class Maker { public: Maker() { a = 0; } void SetA(int val) { a = val; } //没有返回值，也没有void operator bool() { if (a <= 0) { return false; } return true; } bool operator!() { if (a <= 0) { return true; } return false; } operator int() { return 10; } public: int a; }; void test() { Maker m; m.SetA(10); if (m) { cout << "真" << endl; } else { cout << "假" << endl; } if (!m) { cout << "真" << endl; } else { cout << "假" << endl; } int b = (int) m; cout << b << endl; } int main() { test(); getchar(); return EXIT_SUCCESS; } ~~~