Fundamental questions of C++

The following are the initial questions asked by a technical recruiter for a good project in C++. Have a look and hope this helps.

What is the difference between an ARRAY and a LIST?

-->Array is collection of homogeneous elements.
-->List is collection of heterogeneous elements.

-->For Array memory allocated is static and continuous.
-->For List memory allocated is dynamic and Random.

-->Array: User need not have to keep in track of next memory allocation.
-->List: User has to keep in Track of next location where memory is allocated.

-->Array uses direct access of stored members
-->List uses sequencial access for members.

//With Array you have direct access to memory position 5
Object x = a[5]; // x takes directly a reference to 5th element of array

//With the list you have to cross all previous nodes in order to get the 5th node:
list mylist;
list::iterator it;

for( it = list.begin() ; it != list.end() ; it++ )
{
if( i==5)
{
x = *it;
break;
}
i++;
}

What is the word you will use when defining a function in base class to allow this function to be a polimorphic function?

-->Virtual

What are 2 ways of exporting a function from a DLL?
1.Taking a reference to the function from the DLL instance.
2. Using the DLL ’s Type Library

What is the difference between Mutex and Binary semaphore?

semaphore is used to synchronize processes. where as mutex is used to provide synchronization between threads running in the same process.


STL Containers - What are the types of STL containers?
There are 3 types of STL containers:

1. Adaptive containers like queue, stack
2. Associative containers like set, map
3. Sequence containers like vector, deque

Describe two ways where you can prevent a class from being instantiated.

--> Declare all static methods/functions.
--> Declare a private constructor.

Difference between DELETE, TRUNCATE and DROP statements in SQL

--> DELETE
- DML statement
- used to remove rows from a table
- WHERE clause can be sued to remove only some rows.
- After performing DELETE operation you can commit or rollback the transaction to make the change permenant or undo it.
- This operation will cause all TRIGGERS on table to fire.

--> TRUNCATE
- DDL statement
- removes all rows from a table
- operation cannot be rolled back and no triggers will be fired.
- TRUNCATE is faster and doesn't use as much undo space as DELETE.

--> DROP
- DDL statement
- removes a table from a database
- all the tables' rows, indexes and privileges will also be removed.
- No DML triggers will be fired.
- Operation cannot be rolled back.

From Oracle 10g a table can be undropped.
FLASHBACK TABLE emp TO BEFORE DROP
Flashback Complete