300+ TOP Wipro Technical Interview Questions and Answers

• The C programming language manages memory statically, automatically, or dynamically.
• Static-duration variables are allocated in main memory, usually along with the executable code of the program, and persist for the lifetime of the program
• Automatic-duration variables are allocated on the stack and come and go as functions are called and return.
• For static-duration and automatic-duration variables, the size of the allocation is required to be compile-time constant.
• Dynamic memory allocation in which memory is more explicitly (but more flexibly) managed, typically, by allocating it from the heap, an area of memory structured for this purpose.
• In C, the library function malloc is used to allocate a block of memory on the heap. The program accesses this block of memory via a pointer that malloc returns. When the memory is no longer needed, the pointer is passed to free which deallocates the memory so that it can be used for other purposes.

An operating system (OS) is a set of software that manages computer hardware resources and provides common services for computer programs.

To act as interface between hardware and users, an operating system must be able perform the following functions:

1. Enabling startup application programs. Thus, the operating system must have:

• A text editor
• A translator
• An editor of links

2. The allocation of resources needed to execute programs is done by identifying: the programs that are running, the need for memory, peripheral devices and data protection requirements.

3. Facilities for data compression, sorting, mixing, cataloging and maintenance of libraries, through utility programs available.

4. Plan implementation works according to certain criteria, for efficient use of central processing unit.

5. Assisting implementation of programs through computer-user communication system, at both hardware and software level.

Examples of operating systems:
BS2000,BS3000,DOS,PC-DOS,MS-DOS,LINUX,SOLARIS,MAC OS,UNIX,WINDOWS

An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.An IP address serves two principal functions: host or network interface identification and location addressing.

A UNIQUE constraint is similar to PRIMARY key, but you can have more than one UNIQUE constraint per table. Contrary to PRIMARY key UNIQUE constraints can accept NULL but just once. If the constraint is defined in a combination of fields, then every field can accept NULL and can have some values on them, as long as the combination values is unique.

Project plan, Requirements, Design, Coding, Testing, Re-coding and design, Development, Maintenance.

Both an abstract class and an interface are specific types of computer objects that allow a programmer to loosely define one type of object as if it were another type, while retaining all of the object’s original properties. While multiple different computer languages use one or both of these concepts, Java is the most well-known. Abstract classes and interfaces have a variety of similarities, but also incorporate significant differences in structure, syntax, and usage.

SQL> delete from table_name where rowid not in (select max(rowid) from table group by duplicate_values_field_name);

SQL Profiler utility allows us to basically track connections to the SQL Server and also determine activities such as which SQL Scripts are running, failed jobs etc.

Active objects are one which instigate an interaction which owns a thread and they are responsible for handling control to other objects. In simple words it can be referred as client.

Passive objects are one, which passively waits for the message to be processed. It waits for another object that requires its services. In simple words it can be referred as server.

Static modeling is used to specify structure of the objects that exist in the problem domain. These are expressed using class, object and USECASE diagrams.

But Dynamic modeling refers representing the object interactions during runtime. It is represented by sequence, activity, collaboration and statechart diagrams.

Program counter holds the address of either the first byte of the next instruction to be fetched for execution or the address of the next byte of a multi byte instruction, which has not been completely fetched. In both the cases it gets incremented automatically one by one as the instruction bytes get fetched. Also Program register keeps the address of the next instruction.

CREATE procedure – is a stored procedure, which is a saved collection of Transact-SQL statements that can take and return user-supplied parameters.

• Reduced client/server traffic
• Efficient reuse of code and programming abstraction
• Enhanced security controls

XML is case sensitive when uppercase and lowercase characters are treated differently.

Element type names, Attribute names, Attribute values, All general and parameter entity names, and data content (text), are case-sensitive.

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.

A property is a member that provides access to an attribute of an object or a class. Examples of properties include the length of a string, the size of a font, the caption of a window, the name of a customer, and so on.

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

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.

It 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.

Precondition:
A condition that should return true when a member function is invoked. In order to use a function correctly a precondition should return true. If a precondition fails to hold, an operation will not take responsibility to perform any action of sensibility. For example, the interface invariants of stack class respond nothing about pushing even though the stack is already full. In this scenario, sinful () is a precondition for push operation.

Post-Condition:
A condition that should return true before returning from an invoked function. In order to use a function correctly a post condition should return true. Taking a stack as an example, is empty () must necessarily be true after pushing the element into the stack when an element is pushed. The function is empty () is a post condition.

The Document Object Model (DOM) is a cross-platform and language-independent convention for representing and interacting with objects in HTML, XHTML and XML documents.[1] Objects in the DOM tree may be addressed and manipulated by using methods on the objects. The public interface of a DOM is specified in its application programming interface (API).

Difference between overloading and overriding in programming language is:

1. 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.
2. Overloading does not block inheritance from the superclass whereas overriding blocks inheritance from the superclass.
3. In overloading, separate methods share the same name whereas in overriding, subclass method replaces the superclass.
4. Overloading must have different method signatures whereas overriding must have same signature.

There are 5 operators which cannot be overloaded. They are:

1. .* – class member access operator
2. :: – scope resolution operator
3. . – dot operator
4. ?:: – conditional operator
5. Sizeof() – operator

Note:-
This is possible only in C++.

In programming languages, polymorphism means that some code or operations or objects behave differently in different contexts.

For example, the + (plus) operator in C++:

4 + 5

3.14 + 2.0

s1 + “bar”

In C++, that type of polymorphism is called overloading.

Typically, when the term polymorphism is used with C++, however, it refers to using virtual methods, which we’ll discuss shortly.

The default member and base class access specifiers are different.
The C++ struct has all the features of the class. The only differences are that a struct defaults to public member access and public base class inheritance, and a class defaults to the private access specifier and private base class inheritance.