Basic and Advance Programming Interview Questions And Answers

Python is an interpreted, interactive, object-oriented programming language. It is often compared to Tcl, P e r l, Scheme or Java.

Python combines remarkable power with very clear syntax. It has modules, classes, exceptions, very high level dynamic data types, and dynamic typing. There are interfaces to many system calls and libraries, as well as to various windowing systems (X11, Motif, Tk, Mac, MFC, wxWidgets). New built-in modules are easily written in C or C++. Python is also usable as an extension language for applications that need a programmable interface.

The Python implementation is portable: it runs on many brands of UNIX, on Windows, OS/2, Mac, Amiga, and many other platforms.

The Python implementation is copyrighted but freely usable and distributable, even for commercial use.

A class that is declared without any access modifiers is said to have package access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

A class does not inherit constructors from any of its super classes.

Overriding is used to redefines only the methods, but shadowing redefines the entire element.

Multithreading is the mechanism in which more than one thread run independent of each other within the process in any programming language such as C, C++, Java etc...

Inner class in Programming:
classes defined in other classes, including those defined in methods are called inner classes. An inner class can have any accessibility including private.

Anonymous class in Programming:
Anonymous class is a class defined inside a method without a name and is instantiated and declared in the same place and cannot have explicit constructors.

Before 1994 there were different methodologies like Rumbaugh, Booch, Jacobson, Meyer etc who followed their own notations to model the systems.
The developers were in a dilemma to choose the method which best accomplishes their needs. This particular span was called as “method-wars”

The Three amigos namely,
James Rumbaugh (OMT): A veteran in analysis who came up with an idea about the objects and their Relationships (in particular Associations).
Grady Booch: A veteran in design who came up with an idea about partitioning of systems into subsystems.
Ivar Jacobson (Objectory): The father of USECASES, who described about the user and system interaction.

Downcasting concept is the casting from a general to a more specific type, i.e. casting down the hierarchy in programming.

No, method can not be overloaded because the methods can be called without using their return type in which case there is ambiguity for the compiler in programming languages.

Object oriented programming languages directly represent the real life objects. The features of OOPL as inheritance, polymorphism, encapsulation makes it powerful.

1. In procedural program, programming logic follows certain procedures and the instructions are executed one after another. In OOP program, unit of program is object, which is nothing but combination of data and code.

2. In procedural program, data is exposed to the whole program whereas in OOPs program, it is accessible with in the object and which in turn assures the security of the code.

An argument can be passed in two ways in a programming language. They are Pass by Value and Passing by Reference.

Passing by value: This method copies the value of an argument into the formal parameter of the subroutine.

Passing by reference: In this method, a reference to an argument (not the value of the argument) is passed to the parameter.

Difference between overloading and overriding in programming language is:

a) In overloading, there is a relationship between methods available in the same class whereas in overriding, there is relationship between a superclass method and subclass method.

b) Overloading does not block inheritance from the superclass whereas overriding blocks inheritance from the superclass.

c) In overloading, separate methods share the same name whereas in overriding, subclass method replaces the superclass.

d) Overloading must have different method signatures whereas overriding must have same signature.

A super class is a class that is inherited in programming whereas the sub class is a class that does the inheriting in programming.

An object-oriented programming language (also called an OO language) is one that allows or encourages, to some degree, object-oriented programming methods.

Simula (1967) is generally accepted as the first language to have the primary features of an object-oriented language. It was created for making simulation programs, in which what came to be called objects were the most important information representation. Smalltalk (1972 to 1980) is arguably the canonical example, and the one with which much of the theory of object-oriented programming was developed.

OO languages can be grouped into several broad classes, determined by the extent to which they support all features and functionality of object-orientation and objects: classes, methods, polymorphism, inheritance, and reusability.

A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.

Object Oriented Development (OOD) (Booch 1991,1994).
Object Oriented Analysis and Design (OOA/D) (Coad and Yourdon 1991).
Object Modeling Techniques (OMT) (Rumbaugh 1991).
Object Oriented Software Engineering (Objectory) (Jacobson 1992).
Object Oriented Analysis (OOA) (Shlaer and Mellor 1992).
The Fusion Method (Coleman 1991).

Persistent refers to an object’s ability to transcend time or space. A persistent object stores/saves its state in a permanent storage system with out losing the information represented by the object.
A non-persistent object is said to be transient or ephemeral. By default objects are considered as non-persistent.

Aggregation is the relationship between the whole and a part. We can add/subtract some properties in the part (slave) side. It won’t affect the whole part.
Best example is Car, which contains the wheels and some extra parts. Even though the parts are not there we can call it as car.
But, in the case of containment the whole part is affected when the part within that got affected. The human body is an apt example for this relationship. When the whole body dies the parts (heart etc) are died.

A modifier, also called a modifying function is a member function that changes the value of at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ‘mutators’. Example: The function mod is a modifier in the following code snippet:

class test
{
int x,y;
public:
test()
{
x=0; y=0;
}
void mod()
{
x=10;
y=15;
}
};

Template class: A generic definition or a parametrized class not
instantiated until the client provides the needed information. It’s
jargon for plain templates.

Class template: A class template specifies
how individual classes can be constructed much like the way a class
specifies how individual objects can be constructed. It’s jargon for
plain classes.

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 PrintVal()
{
cout << "The value is " << *ptr;
}
};

void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}

int main()
{
Sample s1 = 10;
SomeFunc(s1);
s1.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.

Message in Programming:
* Objects communicate by sending messages to each other.
* A message is sent to invoke a method.

Method in Programming:
* Provides response to a message.
* It is an implementation of an operation.

Analysis: It is the process of determining what needs to be done before how it should be done. In order to accomplish this, the developer refers the existing systems and documents. So, simply it is an art of discovery.

Design:It is the process of adopting/choosing the one among the many, which best accomplishes the users needs. So, simply, it is compromising mechanism.