Dynamic Constructor in C++ with Examples

#include <iostream>
using namespace std;

class geeks {
    const char* p;

public:
    // default constructor
    geeks()
    {

        // allocating memory at run time
        p = new char[6];
        p = "geeks";
    }

    void display() { cout << p << endl; }
};

int main()
{
    geeks obj;
    obj.display();
}

#include <iostream>
using namespace std;

class geeks {
    int* p;

public:
    // default constructor
    geeks()
    {

        // allocating memory at run time
        // and initializing
        p = new int[3]{ 1, 2, 3 };

        for (int i = 0; i < 3; i++) {
            cout << p[i] << " ";
        }

        cout << endl;
    }
};

int main()
{

    // five objects will be created
    // for each object
    // default constructor would be called
    // and memory will be allocated
    // to array dynamically
    geeks* ptr = new geeks[5];
}

#include <iostream>
using namespace std;

class geeks {
    int* p;

public:
    // default constructor
    geeks()
    {

        // allocating memory at run time
        p = new int;
        *p = 0;
    }

    // parameterized constructor
    geeks(int x)
    {
        p = new int;
        *p = x;
    }
    void display() 
    { 
      cout << *p << endl;
    }

    // Deallocate the dynamically allocated memory
    ~geeks() 
    { 
      delete p; 
    }
};

int main()
{

    // default constructor would be called
    geeks obj1 = geeks();
    obj1.display();

    // parameterized constructor would be called
    geeks obj2 = geeks(7);
    obj2.display();
}