Interview : C++ Interview Questions (Page - 5)
What are the access
privileges in C++? What is the default access level?
The access privileges in C++ are private, public and protected. The default
access level assigned to members of a class is private. Private members of a
class are accessible only within the class and by friends of the class.
Protected members are accessible by the class itself and it's sub-classes.
Public members of a class can be accessed by anyone.
What
is a nested class? Why can it be useful?
A nested class is
a class enclosed within the scope of another class. For example:
// Example 1: Nested class
//
class OuterClass
{
class NestedClass
{
// ...
};
// ...
};
Nested classes are useful for organizing code and controlling access and
dependencies.
Nested classes obey access rules just like other parts of a class do; so, in
Example 1, if
NestedClass is public then any code can name it as OuterClass::NestedClass.
Often nested
classes contain private implementation details, and are therefore made private;
in Example
1, if NestedClass is private, then only OuterClass's members and friends can use
NestedClass.
When you instantiate as outer class, it won't instantiate inside class.
What
is a local class? Why can it be useful?
local class is a
class defined within the scope of a function -- any function, whether a
member function or a free function. For example:
// Example 2: Local class
//
int f()
{
class LocalClass
{
// ...
};
// ...
};
Like nested classes, local classes can be a useful tool for managing code
dependencies.
Can
a copy constructor accept an object of the same class as parameter, instead of
reference of the object?
No. It is
specified in the definition of the copy constructor itself. It should generate
an error if a programmer specifies a copy constructor with a first argument that
is an object and not a reference.
(From Microsoft) Assume I have a linked list contains all of the alphabets from ‘A’ to ‘Z’. I want to find the letter ‘Q’ in the list, how does you perform the search to find the ‘Q’?
How
do you write a function that can reverse a linked-list? (Cisco System)
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;
}
}
How
do you find out if a linked-list has an end? (i.e. the list is not a cycle)
You can find out
by using 2 pointers. One of them goes 2 nodes each time. The second one goes at
1 nodes each time. If there is a cycle, the one that goes 2 nodes each time will
eventually meet the one that goes slower. If that is the case, then you will
know the linked-list is a cycle.
How
can you tell what shell you are running on UNIX system?
You can do the
Echo $RANDOM. It will return a undefined variable if you are from the C-Shell,
just a return prompt if you are from the Bourne shell, and a 5 digit random
numbers if you are from the Korn shell. You could also do a ps -l and look for
the shell with the highest PID.
What
is Boyce Codd Normal form?
A relation schema
R is in BCNF with respect to a set F of functional dependencies if for all
functional dependencies in F+ of the form a->b, where a and b is a subset of
R, at least one of the following holds:
• a->b is a trivial functional dependency (b is a subset of a)
• a is a superkey for schema R
Could you tell something about the Unix System Kernel?
The kernel is the heart of the UNIX openrating system, it’s reponsible for
controlling the computer’s resouces and scheduling user jobs so that each one
gets its fair share of resources.
What is a Make file?
Make file is a utility in Unix to help compile large programs. It helps by
only compiling the portion of the program that has been changed.
How
do you link a C++program to C functions?
By using the
extern "C" linkage specification around the C function declarations.
Explain the scope resolution operator.
Design and implement a String class that satisfies the following:
Supports embedded nulls
Provide the following methods (at least)
Constructor
Destructor
Copy constructor
Assignment operator
Addition operator (concatenation)
Return character at location
Return substring at location
Find substring
Provide versions of methods for String and for char* arguments
Suppose that data is an array of 1000 integers. Write a single function call
that will sort
the 100 elements data [222] through data [321].
Answer: quicksort ((data + 222), 100);
