Creating a class object in c++

Question

First i am from JAVA.

In java we create class object like this.

Example example=new Example();

The Example class can have constructor

Answer 1

1)What is the difference between both the way of creating class objects.

First one is a pointer to a constructed object in heap (by new). Second one is an object that implicitly constructed. (Default constructor)

2)If i am creating object like Example example; how to use that in an singleton class.

It depends on your goals, easiest is put it as a member in class simply.

A sample of a singleton class which has an object from Example class:

class Sample
{

    Example example;

public:

    static inline Sample *getInstance()
    {
        if (!uniqeInstance)
        {
            uniqeInstance = new Sample;
        }
        return uniqeInstance;
    }
private:
    Sample();
    virtual ~Sample();
    Sample(const Sample&);
    Sample &operator=(const Sample &);
    static Sample *uniqeInstance;
};

Answer 2

Example example;

Here example is an object on the stack.

Example* example=new Example();

This could be broken into:

Example* example;
....
example=new Example();

Here the first statement creates a variable example which is a "pointer to Example". When the constructor is called, memory is allocated for it on the heap (dynamic allocation). It is the programmer's responsibility to free this memory when it is no longer needed. (C++ does not have garbage collection like java).