interpreter design pattern example

/******************************************************************* * File : interpreter-pattern.cpp (interpreter design pattern example) * Author : Saurabh Gupta * Description : CInterpreter processes commands and performs actions * based on its input. Here we create a simple command * language consisting of single characters. * Date : PM 05:20 29 December 2011 * Source : http://www.ccplusplus.com/2011/07/design-pattern-guide-with-example-and.html * Note : ******************************************************************/ #include <string> #include <iostream> #include <stdexcept> using namespace std; class CInterpreter { public: template<typename It> void run(It from, It to) { for(It i=from; i!=to; ++i) { switch(*i) { case 'h': cout << "Hello"; break; case ' ': cout << ' '; break; case 'w': cout << "world"; break; case '!': cout << '!'; break; case 'n': cout << endl; break; default: throw runtime_error("Unknown command"); } } } }; void helloworld(const string & script) { CInterpreter().run(script.begin(), script.end()); } int main() { helloworld("h w!n"); return 0; } /* * OUTPUT * [sgupta@rhel6x64 interpreter]$ c++ interpreter-pattern.cpp -o interpreter-pattern [sgupta@rhel6x64 interpreter]$ ./interpreter-pattern Hello world! [sgupta@rhel6x64 interpreter]$ */ See Also:

Design pattern Concept and Sample Codes