// Prog: callpow.cpp // Define and call a function for computing powers. #include // PRE: e >= 0 || b != 0.0 // POST: return value is b^e double pow (double b, int e) { double result = 1.0; if (e < 0) { // b^e = (1/b)^(-e) b = 1.0/b; e = -e; } for (int i = 0; i < e; ++i) result *= b; return result; } int main() { std::cout << pow( 2.0, -2) << "\n"; // outputs 0.25 std::cout << pow( 1.5, 2) << "\n"; // outputs 2.25 std::cout << pow( 5.0, 1) << "\n"; // outputs 5 std::cout << pow( 3.0, 4) << "\n"; // outputs 81 std::cout << pow(-2.0, 9) << "\n"; // outputs -512 return 0; }