Memory Allocation for Objects

Memory Allocation for Objects

• The memory space objects is allocated when they are declared.

The members functions are created and placed in the memory only when they are defined as a part of a class specification.

• As the objects are using the same old member functions of the belonging class, no separate memory space is created for these  function when objects are created.

• Only for the member variables the separate memory space is created for each object.

• Fig. 2.12.1 illustrates this concept.

•  The memory required by any object is dependent upon following factors

 1. size of non static data members of the class.

2. order of data members.

3. Byte padding.

Consider following example ‒

class Test

{

    float a;

    int b;

    static int c;

     char d;

};

Test obj;

For obj size will be sizeof(a)+sizeof(b)+sizeof(d)=4+2+1=7 bytes. Note that the size of static members is not included in this calculation.Static members are really not part of the class object. They won't be included in object's layout.

Review Questions

1. Discuss instantiation of objects.

2. Discuss memory allocation for objects.