Proxy Pattern

Proxy Pattern comes under Structural Pattern.

According to Gang Of Four Intent of Proxy Pattern is to Provide a surrogate or placeholder for another object to control access to it.

UML DIAGRAM:

SAMPLE CODE:

#include <iostream>

using namespace std;

class Vote {
public:
    virtual void castVote(string name, int age) = 0;
};

class VoteSystem : public Vote {
public:
    void castVote(string name, int age)
    {
        cout << "NAME : " << name << ", AGE : " << age << " Casted Vote Successfully" << endl;
    }
};

class IndianVoteSystem : public Vote { // Proxy class
    Vote* voteOper;

public:
    IndianVoteSystem()
    {
        voteOper = new VoteSystem();
    }

    void castVote(string name, int age)
    {
        if (age >= 18) { // if age is more than 18 cast vote
            voteOper->castVote(name, age);
        }
        else {
            cout << age << " Years is Not Eligible Age to Cast Vote in India" << endl;
        }
    }
};

int main()
{
    string name;
    int age;

    Vote* indiaPoll = new IndianVoteSystem();

    cout << "Name ? "; cin >> name;
    cout << "Age  ? "; cin >> age;

    indiaPoll->castVote(name, age);

    return 0;

}

OUTPUT:

Name ? hirthik
Age  ? 16
16 Years is Not Eligible Age to Cast Vote in India

Name ? sharma

Age  ? 34

NAME : sharma, AGE : 34 Casted Vote Successfully

Name ? rahul

Age  ? 18

NAME : rahul, AGE : 18 Casted Vote Successfully

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