C++ using namespace program

Program 1

#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 2

#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 3

#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 4

#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