Wednesday, April 30, 2008

Data Structures Interview Questions Set -2

Data Structures Interview Questions Set -2

What is the bucket size, when the overlapping and collision occur at same time?
One. If there is only one entry possible in the bucket, when the collision occurs, there is no way to accommodate the colliding value. This results in the overlapping of values.

In an AVL tree, at what condition the balancing is to be done?
If the pivotal value (or the Height factor) is greater than 1 or less than 1.

Minimum number of queues needed to implement the priority queue?
Two. One queue is used for actual storing of data and another for storing priorities.

How many different trees are possible with 10 nodes ?
1014 - For example, consider a tree with 3 nodes(n=3), it will have the maximum combination of 5 different (ie, 23 - 3 =? 5) trees.

What is a node class?
A node class is a class that, relies on the base class for services and implementation, provides a wider interface to 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.

When can you tell that a memory leak will occur?
A memory leak occurs when a program loses the ability to free a block of dynamically allocated memory.

What is placement new?
When you want to call a constructor directly, you use the placement new. Sometimes you have some raw memory that’s already been allocated, and you need to construct an object in the memory you have. Operator new’s special version placement new allows you to do it.
class Widget
{
public :
Widget(int widgetsize);

Widget* Construct_widget_int_buffer(void *buffer,int widgetsize)
{
return new(buffer) Widget(widgetsize);
}
};
This function returns a pointer to a Widget object that’s constructed within the buffer passed to the function. Such a function might be useful for applications using shared memory or memory-mapped I/O, because objects in such applications must be placed at specific addresses or in memory allocated by special routines.

List out the areas in which data structures are applied extensively ?
Compiler Design, Operating System, Database Management System, Statistical analysis package, Numerical Analysis, Graphics, Artificial Intelligence, Simulation

If you are using C language to implement the heterogeneous linked list, what pointer type will you use?
The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them. It is not possible to use ordinary pointers for this. So we go for void pointer. Void pointer is capable of storing pointer to any type as it is a generic pointer type.

What is the data structures used to perform recursion?
Stack. Because of its LIFO (Last In First Out) property it remembers its caller so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls. Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.

Whether Linked List is linear or Non-linear data structure?
According to Access strategies Linked list is a linear one.

According to Storage Linked List is a Non-linear one

Tell how to check whether a linked list is circular ?
Create two pointers, each set to the start of the list. Update each as follows:

while (pointer1)

{
pointer1 = pointer1->next;
pointer2 = pointer2->next; if (pointer2) pointer2=pointer2->next;
if (pointer1 == pointer2)

? ? ? ? ? ? {
print (\”circular\n\”);
}
}

What is the difference between ARRAY and STACK?
STACK follows LIFO. Thus the item that is first entered would be the last removed.

In array the items can be entered or removed in any order. Basically each member access is done using index. No strict order is to be followed here to remove a particular element.

What is the difference between NULL AND VOID pointer?
NULL can be value for pointer type variables.
VOID is a type identifier which has not size.
NULL and void are not same. Example: void* ptr = NULL;

What is precision?
Precision refers the accuracy of the decimal portion of a value. Precision is the number of digits allowed after the decimal point.

What is impact of signed numbers on the memory?
Sign of the number is the first bit of the storage allocated for that number. So you get one bit less for storing the number. For example if you are storing an 8-bit number, without sign, the range is 0-255. If you decide to store sign you get 7 bits for the number plus one bit for the sign. So the range is -128 to +127.

How memory is reserved using a declaration statement ?
Memory is reserved using data type in the variable declaration. A programming language implementation has predefined sizes for its data types.

For example, in C# the declaration int i; will reserve 32 bits for variable i.

A pointer declaration reserves memory for the address or the pointer variable, but not for the data that it will point to. The memory for the data pointed by a pointer has to be allocated at runtime.

The memory reserved by the compiler for simple variables and for storing pointer address is allocated on the stack, while the memory allocated for pointer referenced data at runtime is allocated on the heap.

How many parts are there in a declaration statement?

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