Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location or it points to some location whose value is not available for modification.
int *i=0x400 //i points to address 400
*i=0; //set the value of memory location pointed by i.
Incomplete types are otherwise called uninitialized pointers.
What Is A Dangling Pointer In C++?
A dangling pointer arises when you use the address of an object after its lifetime is over. This may occur in situations like returning addresses of the automatic variables from a function or using the address of the memory block after it is freed. The following code snippet shows this
class Sample
{
public:int *ptr; Sample(int i)
{
ptr = new int(i);
}
~Sample()
{
delete ptr;
}
void PrintValO
{
cout« "The value is " « *ptr;
}
};
void SomeFunc(Sample x)
{
cout« "Say i am in someFunc " « endl;
}
int main()
{
Sample si = 10;
SomeFunc(sl);
sl.PrintVal();
}
In the above example when PrintVal() function is called it is called by the pointer that has been freed by the destructor in SomeFunc.
Differentiate Between The Message And Method In C++?
Message in C++
Objects communicate by sending messages to each other.
A message is sent to invoke a method in C++.
Method in C++
Provides response to a message.
It is an implementation of an operation in C++.
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What Is An Adaptor Class Or Wrapper Class In C++?
A class that has no functionality of its own is an Adaptor class in C++. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non-object-oriented implementation.
What Is A Null Object In C++?
It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.
What Is Class Invariant In C++?
A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.
What Do You Mean By Stack Unwinding In C++?
Stack unwinding in C++ is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.
Define Pre-condition And Post-condition To A Member Function In C++?
Precondition: A precondition is a condition that must be true on entry to a member function. A class is used correctly if preconditions are never false. An operation is not responsible for doing anything sensible if its precondition fails to hold. For example, the interface invariants of stack class say nothing about pushing yet another element on a stack that is already full. We say that isful() is a precondition of the push operation.
Post-condition: A post-condition is a condition that must be true on exit from a member function if the precondition was valid on entry to that function. A class is implemented correctly if post-conditions are never false. For example, after pushing an element on the stack, we know that isempty() must necessarily hold. This is a post-condition of the push operation.
What Are The Conditions That Have To Be Met For A Condition To Be An Invariant Of The Class?
The condition should hold at the end of every constructor.
The condition should hold at the end of every mutator (non-const) operation.
What Are Proxy Objects In C++?
Objects that stand for other objects are called proxy objects or surrogates.
template <class t=""> class Array2D
{
public
class Array ID
{
public
T&operator[](int index);
const T&operator[](int index)const;
};
Array ID operator[] (int index);
const Array ID operator[] (int index) const;
};
The following then becomes legal
Array2D<float>data(l0,20); cout«data[3][6]; // fine
Here data[3] yields an ArraylD object and the operator [] invocation on that object yields the float in position(3,6) of the original two dimensional array. Clients of the Array 2D class need not be aware of the presence of the ArraylD class. Objects of this latter class stand for one-dimensional array objects that, conceptually, do not exist for clients of Array2D. Such clients program as if they were using real, live, two-dimensional arrays. Each ArraylD object stands for a one-dimensional array that is absent from a conceptual model used by the clients of Array2D. In the above example, ArraylD is a proxy class. Its instances stand for one-dimensional arrays that, conceptually, do not exist.
Name Some Pure Object Oriented Languages?
pure object oriented languages are Smalltalk, Java, Eiffel, Sather.
What Is A Node Class In C++?
A node class is a class that,
relies on the base class for services and implementation.
provides a wider interface to the users than its base class.
relies primarily on virtual functions in its public interface.
depends on all its direct and indirect base class.
can be understood only in the context of the base class.
can be used as base for further derivation.
can be used to create objects.
A node class is a class that has added new services or functionality beyond the services inherited from its base class.
What Is An Orthogonal Base Class In C++?
If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.
What Is A Container Class? What Are The Types Of Container Classes In C++?
A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.
How Do You Write A Function That Can Reverse A Linked-list In C++?
void reverselist(void)
{ if(head==0)
return;
if(head-<next==0)
return;
if(head-<next==tail)
{
head-<next = 0;
tail-<next = head;
} else
{
node* pre = head;
node* cur = head-<next;
node* curnext = cur-<next; head-<next = 0; cur-<next = head;
for(; curnext !=0;)
{
cur-<next = pre;
pre = cur;
cur = curnext;
curnext = curnext-<next;
}
curnext-<next = cur;
}
}