ccplusplus.com: strategy design pattern example

Thursday, January 5, 2012

strategy design pattern example

/*******************************************************************
 * File         :   strategy-pattern.cpp
 * Author       :   Saurabh Gupta
 * Description  :   strategy design pattern example
 *                  Strategy is an algorithm that you pass into a 
 *                  function or class that uses the strategy.  The 
 *                  idea is that you can provide a different strategy 
 *                  to achieve something different.
 * Date         :   PM 08:11 05 January 2012
 * Source       :   http://www.ccplusplus.com/2011/07/design-pattern-guide-with-example-and.html
 * Note         :   
 *******************************************************************/
 
 #include <iostream>
 #include <string>

using namespace std;
 
 class CStrategyPattern {
     public:
        virtual ~CStrategyPattern() {
        }
        virtual string m_format(const string &, const string &) const=0;
 };

class Formatter : public CStrategyPattern {
     public:
        string m_format(const string & s1, const string & s2) const
        {
            return s1 + "" + s2 + "";
        }
 };

void display_message(const CStrategyPattern & strategy){
 cout << strategy.m_format("c", "cplusplus.com") << endl;
 }

int main() {
 display_message(Formatter());
 return 0;
 }
 
/*
 * OUTPUT
 *
 [sgupta@rhel55x86 strategy]$ c++ strategy-pattern.cpp -o strategy-pattern
 [sgupta@rhel55x86 strategy]$ ./strategy-pattern
 ccplusplus.com
 [sgupta@rhel55x86 strategy]$
*/

1 comment:

AnonymousMarch 12, 2015 at 5:43 PM
Strategy pattern becomes evident in situations where there are more than 2 different behaviors. Having a pure virtual function and calling the over-ridden method does not adequately bring out the strategy pattern.
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