C++ Useful Program

Program 1

#include

#include

using namespace std;

class A

{

   int aid;

public:

   A(int x)

   {

      aid = x;

    }

   void print()

   {

       cout << "A::aid = " <

    }

};

class B

{

    int bid;

public:

    static A a;

    B (int i)

   {

      bid = i;

   }

};

int main()

{

  B b(10);

  b.a.print();

  return 0;

}

Program 2

#include

#include

using namespace std;

class A

{

    int id;

    static int count;

public:

    A()

    {

        count++;

        id = count;

        cout << "constructor called " << id << endl;

    }

    ~A()

    {

        cout << "destructor called " << id << endl;

    }

};

int a::count = 0;

int main()

{

    A a[2];

    return 0;

}

Output

constructor called 1

constructor called 2

destructor called 2

destructor called 1

Program 3

#include

#include

using namespace std;

class A

{

    int id;

public:

    A (int i)

   {

    id = i;

    }

    void print ()

    {

     cout << id << endl;

    }

};

int main()

{

    A a[2];

    a[0].print();

    a[1].print();

    return 0;

}

Program 4

#include

#include

using namespace std;

class A

{

public:

    void print()

    {

     cout << "A::print()";

    }

};

class B : private A

{

public:

    void print()

    {

     cout << "B::print()";

    }

};

class C : public B

{

public:

    void print()

    {

     A::print();

     }

};

int main()

{

    C b;

    b.print();

}

Program 5

#include

#include

using namespace std;

class base

{

public:

virtual void show() 

{

  cout<<" In Base \n";

           }

};

class derived: public base

{

    int x;

public:

    void show()

    {

    cout<<"In derived \n";

    }

    derived()  

    {

    x = 10;

    }

    int getX() const

   {

     return x;

    }

};

int main()

{

    derived d;

    base *bp = &d;

    bp->show();

    cout << bp->getX();

    return 0;

}

Program 6

#include

#include

using namespace std;

class test

{

    int value;

public:

    test(int v = 0)

    {

        value = v;

     }

 int getvalue() 

    {

         return value;

     }

};

int main()

{

    const test t;

    cout << t.getvalue();

    return 0;

}

Program 7

#include

#include

using namespace std;

class Bbase 

{

public:

    int fun()      

      { 

          cout << "Base::fun() called"; 

      }

    int fun(int i) 

      { 

       cout << "Base::fun(int i) called"; 

      }

};

class derived: public base 

{

public:

    int fun(char x)   

   { 

      cout << "Derived::fun(char ) called"; 

   }

};

int main() 

{

    derived d;

    d.fun();

    return 0;

}

Program 8

#include 

#include

using namespace std;

class A

{

    public:

    A& operator=(const A&a)

    {

        cout << "A is assignment operator called" << endl;

        return *this;

    }

};

class B

{

    A a[2];

};

int main()

{

    B b1, b2;

    b1 = b2;

    return 0;

}

Output

A is assignment operator called

A is assignment operator called

Program 9

#include

#include

using namespace std;

class test 

{

public:

    void* operator new(size_t size);

    void operator delete(void*);

    test() 

    { 

          cout<<"\n Constructor called"; 

    }

    ~test() 

    { 

        cout<<"\n Destructor called"; 

     }

};

void* test::operator new(size_t size)

{

    cout<<"\n New called";

    void *storage = malloc(size);

    return storage;

}

void test::operator delete(void *p )

{

    cout<<"\n Delete called";

    free(p);

}

int main()

{

    test *m = new test();

    delete m;

    return 0;

}

Output

 New called

 Constructor called

 Destructor called

 Delete called