Technical Interview Questions and Answers [Updated]

There can be nobody in this techy world who has never know about networking and its importance. Network engineering is one of the trendiest jobs of out times.

Earlier, if a person wishing to appear for an interview needs to carefully go through all the books and materials available page by page. But the internet, a networking system has made it all so easy. Regardless of whether you're a fresher or an experienced person, be prepared to face some basic networking questions if you're preparing for a networking interview.

C Programming Interview Questions

Question: What is C language?

Answer: The C programming language is a standardized programming language developed for use on the UNIX operating system. C is the most common programming language for writing system software, although it is also used for writing applications.

Question: What are the different storage classes in C?

Answer: C has three storage types: automatic static and allocated. Variable with block range and automatic processing length without a static specifier. Block scope variables and static specifier variables have static scope. There is also a dynamic scope for global variables (i.e., file scope) with or without the static specifier. Memory obtained from calls to malloc( ), alloc( ) or realloc( ) belongs to the memory class allocated.

Question: What is the output of printf("%d")?

Answer: If we write printf("%d,"x); this means that the x value will be printed by the compiler. But as here, after %d there is nothing, so the compiler will show garbage value in the output window.

Question: What is the difference between printf( ) and sprintf( ) ?

Answer: Sprintf ( ) writes the character array data while printf(...) writes the standard output machine data.

Question: Can you tell how to check whether a linked list is circular?

Answer: Create two points and set them both at the start of the list, program:

while (pointer1) {
pointer1 = pointer1->next;
pointer2 = pointer2->next;
if (pointer2) pointer2=pointer2->next;
if (pointer1 == pointer2) {
print ("circular");
}
}

Question: What is hashing?

Answer: Hashing means grinding up, and that's what hashing is all about. A hashing algorithm's core is a hash function that takes your good, smooth data and grinds it into a random-looking whole.

The concept behind hashing is that some data either does not have an inherent order (such as images) or are expensive to compare. If the data does not have an underlying order, comparison searches can not be performed.

Question: Explain the difference between strings and character arrays?

Answer: A major difference is: string will have static storage length, while string will not have static storage duration as a character set unless the static keyword is used to indicate explicitness.

The multi-byte character sequence we usually call string is used to initialize a static space length range. The width of this set is enough to contain these characters in addition to the terminating NUL code.
It is not specified what happens if this array, i.e., string, is modified.
The same memory field may be shared by two strings of the same value.

Question: Why n++ executes faster than n+1 ?

Answer: To carry out the increment operation, the expression n++ requires a single machine instruction such as INR, while n+1 needs more instructions.

Question: What is the purpose of main( ) function?

Answer: The main ( ) function invokes other functions within it. It is the first function to be written when running a program.

It is a starting function
It returns an int value to the environment that called the program
Recursive calling for main ( ) is also enabled
It is a user-defined function
Execution of the program ends when the main ( ) function closes.
It has two arguments 1) argument count and 2) argument vector

Question: What is the difference between %d and %*d in c language?

Answer: The % d gives the variable's original value and the %* d gives the variable's name.

eg:-

int a=10,b=20;
printf("%d%d",a,b);
printf("%*d%*d",a,b);

Here result for the first printf will be 10,20 and the result for the second printf give memory allocation that can say 1760.

C++ Interview questions

Question: What is C++?

Answer: C++ is an object-oriented programming language. C++ retains almost all elements of the C language, simplifying memory management and adding multiple functions. C++ retains C features that allow access to low-level memory, but also provides the programmer with new tools to improve memory management.

Question: What is a constructor?

Answer: A constructor is used to creating and initialize an object. It also generates a digital feature vtable. It's special in a category from other processes.

What is a constructor? - Technical Interview Questions

Question: What is inheritance?

Answer: Inheritance allows one class to reuse another class' state and actions. The derived class inherits and expands the base class' properties and method implementations by modifying methods and adding additional properties and methods.

Question: What is a class?

Answer: A class is an extended definition of a data structure: it can contain both data and functions instead of holding only data.

Question: How do you know that your class needs a virtual destructor?

Answer: If we have even one virtual function in the class, we need to make a virtual destructor. This will allow you to remove a dynamic object from a base class object through a caller.

Question: What is the difference between realloc() and free()?

Answer: The free subroutine removes a memory block that the malloc subroutine had previously reserved. The undetermined result occurs if the pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will occur.

The realloc subroutine adjusts the size of the memory block referring to the number of bytes defined by the Size parameter by the Pointer parameter and returns a new pointer to the row. The pointer defined by the Pointer parameter must have been generated with the subroutines of malloc, calloc, or reallocation and not dealing with the subroutines of free or reallocation.

Question: Write a function that can reverse a linked-list?

Answer:

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;
}
}

Question: What is the difference between C++ & Java?

Answer:

C++	Java
Classes and functions can be templated.	Classes and methods can be genericized
Parameters can be any type or integral value.	Reference type parameter only
For each type parameter, separate class or function copies are likely to be created when compiled.	For all types of parameters, there is only one type of class or function is compiled
The templated class or a function's source code must be included, in order to use it	Signature of the class or function from a compiled class is sufficient to use it.
Templates can be specialized	Cannot be specialized (generic)
The bounding type parameter is not allowed but is supported by metaprogramming.	Supports upper and lower bounding of category parameters with "extends" and “super”
For static methods and variables, the type parameter of the templated class can be used	For static methods and variables, the form parameter of the templated class can not be used.
There is no sharing of static variables between classes of different types of parameters.	Static variables are shared among instances of different type class parameters

Question: What is RTTI?

Answer: Runtime type identification (RTTI) allows you to find an object's dynamic form when you only have a pointer or a base type reference. RTTI is the official way to discover the type of an object in standard C++ and to convert a reference or pointer type.

Question: How do virtual functions work in C++?

Answer: A virtual function relies on a virtual table or board. If any of a class's functions are considered virtual, a v-table is built that stores addresses of this class's virtual functions. The compiler also adds in all such classes a secret vptr variable that points to that class's vtable.

If a virtual function in the derived class is not overridden, the vtable in the derived class must store the function address in its parent class.

Operating system Interview Questions:

Question: What is an operating system (OS)?

Answer: An Operating System (OS) is a computer user-hardware interface. There are two main purposes of operating systems. One is to ensure that a computer system works well. Another is that it offers a framework for system development and implementation.

Some popular Operating Systems include Linux, Windows, OS X, VMS, OS/400, AIX, z/OS, etc.

Question: What are the advantages of a multiprocessor system?

Answer: There is a significant increase in throughput with an increased number of processors. However, because they can share resources, it can save more money. Finally, there is also an increase in overall performance.

Question: What is SMP?

Answer: SMP is a short form of Symmetric Multi-Processing. It's the most popular multi-processor device type. Each processor runs an identical copy of the operating system in this system and these copies communicate with each other as needed.

Question: What are the types of Operating System?

Answer:

Batch operating system
Time-sharing operating systems
Distributed operating System
Network operating System
Real-Time Operating System

Question: What is the best page size when designing an operating system?

Answer: Paging size varies from system to system. In order to create a suitable page size, there are numerous factors to consider, such as page table, paging time, and its effect on the overall operating system performance.

Question: What is caching?

Answer: Caching is the storage for limited data and processes using a region of fast memory. Because of its high access speed, cache memory is typically very effective.

Question: Explain why Ubuntu OS is safe and not affected by viruses?

Answer:

It does not accept malicious emails and content, and many security checks will be carried out before any email is opened by users.
Ubuntu uses Linux, i.e. a super-secure O.S system
Unlike other O.S, countless Linux users will be able to see the code at any time and solve the problem if any.

Question: What is the role of paging?

Answer: Paging is a memory management system that allows a process to be non-contiguous in the physical address space. This eliminates the considerable problem of fitting varied chunks of memory in the backup store.

Question: What is the Translation Lookaside Buffer (TLB)?

Answer: In a cached system the base addresses of the last couple of referenced pages are stored in registers called the TLB which helps with faster lookup. TLB includes the most recently used page table entries. Typically, each virtual memory link requires two accesses to physical memory-one to get the correct page table entry and one to get the requested information. It limits the use of TLB in-between to just one physical memory access in TLB-hit cases.

Question: How are server systems classified?

Answer: It is possible to identify database systems as either computer server systems or file server systems. In the first example, customers are provided with an application to submit requests for action. In the second case, there are provisions for creating, accessing, and updating files for clients.

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Technical Interview Questions and Answers [Updated]

Top Technical Interview Questions and Answers

Networking Interview Questions

Question: What is Computer Networking?

Question: What is a gateway?

Question: What is Network Mask?

Question: What are the differences between TCP/UDP?

Question: Compare IPv4 and IPv6 protocol?

Question: What are the different Routing protocol?

Question: What is MAC address?

Question: What are the different types of networking devices?

1. Hub

2. Repeater

3. Router

4. Gateways

5. Bridges

Java Interview Questions

Question: What is JAVA?

Question: Application where it is possible to develop in Java?

Question: Explain Java language specification?

Question: What is RMI and RMI architecture?

Question: What is Servlet chaining?

Question: What is connection pooling?

Question: What are cookies?

Question: How to track a client?

Question: What is JDBC?

Question: What is the difference between JDBC and ODBC?

C Programming Interview Questions

Question: What is C language?

Question: What are the different storage classes in C?

Question: What is the output of printf("%d")?

Question: What is the difference between printf( ) and sprintf( ) ?

Question: Can you tell how to check whether a linked list is circular?

Question: What is hashing?

Question: Explain the difference between strings and character arrays?

Question: Why n++ executes faster than n+1 ?

Question: What is the purpose of main( ) function?

Question: What is the difference between %d and %*d in c language?

C++ Interview questions

Question: What is C++?

Question: What is a constructor?

Question: What is inheritance?

Question: What is a class?

Question: How do you know that your class needs a virtual destructor?

Question: What is the difference between realloc() and free()?

Question: Write a function that can reverse a linked-list?

Question: What is the difference between C++ & Java?

Question: What is RTTI?

Question: How do virtual functions work in C++?

Operating system Interview Questions:

Question: What is an operating system (OS)?

Question: What are the advantages of a multiprocessor system?

Question: What is SMP?

Question: What are the types of Operating System?

Question: What is the best page size when designing an operating system?

Question: What is caching?

Question: Explain why Ubuntu OS is safe and not affected by viruses?

Question: What is the role of paging?

Question: What is the Translation Lookaside Buffer (TLB)?

Question: How are server systems classified?

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