fork download
copy 
  1. #include <iostream>
  2. #include <unordered_map>
  3. #include <string>
  4. #include <cmath>
  5. using namespace std;
  6.  
  7. class Calculator {
  8. private:
  9.     typedef double (*FuncType)(double, double);
  10.  
  11.     static unordered_map<string, FuncType> operator_function;
  12.  
  13.     static double multiply(double num_1, double num_2) {
  14.         cout << "MULTIPLYING!" << endl;
  15.         return num_1 * num_2;
  16.     }
  17.  
  18.     static double exponent(double num_1, double num_2) {
  19.         cout << "EXPONENT!" << endl;
  20.         return pow(num_1, num_2);
  21.     }
  22.  
  23. public:
  24.     static double do_math(string op, double num_1, double num_2) {
  25.         FuncType func = operator_function[op];
  26.         return func(num_1, num_2);
  27.     }
  28. };
  29.  
  30. unordered_map<string, Calculator::FuncType> Calculator::operator_function = {
  31.     {"*",  &Calculator::multiply},
  32.     {"^",  &Calculator::exponent},
  33.     {"**", &Calculator::exponent}
  34.     // and so on ...
  35. };
  36.  
  37. int main() {
  38. 	cout << Calculator::do_math("*", 123, 45) << endl;
  39. 	cout << Calculator::do_math("^", 123, 2) << endl;
  40. 	return 0;
  41. }
Success #stdin #stdout 0.01s 5504KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
MULTIPLYING!
5535
EXPONENT!
15129
https://ideone.com/lCxlAd
language:
C++ 4.3.2 (gcc-4.3.2)
created:
2 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!