#include #include #include using namespace std; //this is observer class class clsGuardian { public: virtual void updateInfo(int iScore) = 0; virtual void dispay() = 0; }; //this is observer class's implementation class clsPapa : public clsGuardian { string strRelation; int intScore; public: clsPapa() { strRelation = "Papa"; } void updateInfo(int iScore) { intScore = iScore; dispay(); } void dispay() { cout << "------->Thanks from " << strRelation << "... Got info that score for recent test is " << intScore << endl; } }; //this is observer class's implementation class clsGrandPapa : public clsGuardian { string strRelation; int intScore; public: clsGrandPapa() { strRelation = "clsGrandPapa"; } void updateInfo(int iScore) { intScore = iScore; dispay(); } void dispay() { cout << "------->Thanks from " << strRelation << "... Got info that score for recent test is " << intScore << endl; } }; //this is observer class's implementation class clsMom : public clsGuardian { string strRelation; int intScore; public: clsMom() { strRelation = "Mom"; } void updateInfo(int iScore) { intScore = iScore; dispay(); } void dispay() { cout << "------->Thanks from " << strRelation << "... Got info that score for recent test is " << intScore << endl; } }; //this is subject class class clsStudent { vector vecScores; vector vecGuardian; public: clsStudent() { srand(time(nullptr)); vecScores.reserve(10); } void appearForTest() { cout << endl <<"Please wait....Test is in progress.....!" << endl; int intScore = 1 + rand()%100; cout << "Test score is " << intScore << endl; RegisterResult(intScore); } void RegisterResult(int intScore) { vecScores.emplace_back(intScore); notifyGuardian(intScore); } virtual void registerGuardian(clsGuardian* pGuardian) { vecGuardian.push_back(pGuardian); } void notifyGuardian(int intScore) { for (auto pGuardian : vecGuardian) pGuardian->updateInfo(intScore); } }; int main() { clsStudent objStudent; clsPapa papa; clsGrandPapa GrandPapa; clsMom mom; objStudent.registerGuardian(&papa); objStudent.registerGuardian(&GrandPapa); objStudent.registerGuardian(&mom); for(int i=0;i<10;++i) objStudent.appearForTest(); return 0; }

ObserverPattern_1