Cognizant Interview Questions and Answers for 2025

Computer programs can use preemptive multitasking to share operating systems (OS) and underlying hardware resources. It divides overall operational and computing time among processes and switches resources between them based on predefined parameters. Preemptive multitasking is another term for time-shared multitasking. 

In cooperative multitasking, the operating system never initiates context switching from one process to another. A context switch occurs only when the processes willingly transfer control on a regular basis, or when they are dormant or logically blocked, allowing many programs to execute at the same time. Furthermore, all operations in this multitasking work together to make the scheduling technique function. 

• The memcpy() method copies a given number of bytes from one memory to another. 
• The strcpy() function, on the other hand, is used to copy the contents of one string into another. 
• The memcpy() method manipulates memory rather than values. In contrast, the strcpy() method operates on values rather than memory. 

The practice of utilizing one program's output as an input to another is referred to as plumbing/piping. For example, rather than sending a folder or drive listing to the main screen, it may be piped and given to a file, or it can be sent to the printer to print a printed copy. 

In Linux and other Unix-like operating systems, a pipe is a sort of redirection (the movement of standard output to another place) that is used to convey the output of one command/program/process to another for extra processing. A command's stdout can be linked to another command's stdin on Unix/Linux platforms. This may be accomplished by using the pipe character '|'. 

The following are typical elements of a processed image: 

• User data: This component of user space comprises program data, the user stack area, and programs that may be updated. 
• The collection of instructions that will be performed by the user program. 
• System Stack: Each process is coupled with one or more LIFO (Last In First Out) stacks. Parameters and calling addresses for procedure and system calls are saved here. 
• Process control Block (PCB): Information required by the operating system to control operations. 

Translation TLB (Transaction Look-aside Buffer) is a cache that maintains track of recently used transactions. The TLB contains the most recently utilized page table entries. When a virtual address is handed to the CPU, it examines the TLB. If a page table entry (TLB hit) is present, the frame number is obtained and the actual address is generated. If a page table item is missing from the TLB (TLB miss), the page number is utilized as an index when processing the page table. The TLB first checks to see if the page is already in main memory; if it isn't, a page fault is issued, and the TLB is then changed to include the new page entry.

The resident set is the portion of the processed picture that is really in real memory at any one time. It has been subdivided into subsets, one of which is the working set. The working set is a subset of the resident set that is necessary for execution.

A network device that can function as both a bridge and a router is referred to as a bridge router, or brouter. Similar to a bridge, the router simply forwards packets necessary for established protocols. 

For routable protocols, brouters operate at the network layer; for non-routable systems, they operate at the data link layer. Brouters manage both routable and non-routable qualities by acting as bridges for non-routable protocols and routers for routable protocols. In an internetwork, routers and network bridges are both functions performed by brouters, which are networking equipment. 

You can look for more Cognizant HR interview questions in between this article. 

Rather than speaking in local "languages," all Telnet clients and servers agree to send data and instructions that adhere to the Network Virtual Terminal, a fictitious "virtual" terminal type (NVT). The NVT defines a set of standards for data formatting and transmission, including character set, line termination, and how to convey information about the Telnet session. 

On a terminal, any Telnet client may interact in both its native language and NVT. When a user enters data on a local terminal, it is converted to NVT and transmitted over the network in that format. 

When this information is received by the Telnet server, it is converted from NVT to the format required by the remote host. For transmissions from the server to the client, the same technique is used. 

The Hamming code is a collection of error-correction codes that may be used to detect and rectify faults that may occur during data transfer or storage from one source to another. Redundant bits are additional binary bits that are manufactured and added to the information-carrying bits of a data transmission to ensure that no bits are lost during the transfer. A parity bit is added to binary data to check if the total number of 1s is even or odd. 

Error detection is accomplished using parity bits. The Hamming Code is simply the use of extra parity bits to identify errors. 

A pair of virtual character devices known as a pseudo TTY offer a bidirectional communication channel (or "PTY"). The slave is at one end of the channel and the master is at the other. The slave end of the pseudo-terminal offers an interface that is identical to that of a normal terminal. A process that anticipates being connected to a terminal can open the slave end of a pseudo-terminal, which is then controlled by a program that has opened the master end. Anything written on the master end is sent into the slave end's procedure as if it were a terminal input. However, everything written to the slave end of the pseudo-terminal may be read by the process tied to the master end. Pseudo-terminals are used by network login services, terminal emulators, and other similar applications.  

BufferedWriter is a source of temporary data storage. It's used to generate a buffered character output stream with the output buffer size set to the default. 

The flush() method of the BufferedWriter class in Java is used to flush characters from the buffered writer stream to a file. 

It guarantees that all data items, including the last character, are written to the file. 

The close() method of the Java BufferedWriter class flushes the buffer stream and then closes it. Calling methods like write() and append() after the stream has been closed will result in an error.

Objects that are produced dynamically are kept in heap memory. If objects are produced without management, the memory will run out and the system will crash. 

A garbage collection algorithm is the Mark and Sweep algorithm. It operates in two stages. 

The technique discovers unneeded items in memory in the first phase, and these objects are deleted from memory in the second phase to reclaim the wasted space.  

These are some CTS interview questions

It may be constructed as numerous constructors with distinct arguments, each of which can do a separate activity. In Java, these constructors must have distinct signatures, and a separate set of arguments must be provided to the constructor for error-free compilation. 

public class Employee {  
intuid;  
String name;  
Employee(){  
System.out.println("this a default constructor");  
}  
Employee(inti, String n){  
uid = i;  
name = n;  
}  
public static void main(String[] args) {  
//object creation  
Employee s = new Employee();  
System.out.println("\nDefault Constructor values: \n");  
System.out.println("Employee uid : "+s.uid + "\nEmployee Name : "+s.name);  
System.out.println("\nParameterized Constructor values: \n");  
Employee Employee = new Employee(10, "John");  
System.out.println("Employee uid : "+Employee.uid + "\nEmployee Name : "+Employee.name);  
}  
} 

A virtual function is indeed a member function declared in the base class but overridden by the derived class. The use of virtual functions aids in the achievement of runtime polymorphism. 

• Rules to remember while using virtual functions 
• It cannot be fixed. 
• It should be accessible through the use of a pointer or reference to the base class. 
• A virtual destructor can exist in a class, but not a virtual constructor.  

A binary tree is a non-linear data structure. Every node in the tree has left and right pointers as well as data. The root node is the topmost node. Parent nodes have sub-nodes, but leaf nodes do not.

Binary trees are utilized in binary search tree implementation. They are handy for keeping records without taking up much space.

The divide and conquer method is used for Merge Sort. The issue is divided into smaller problems of the same type until they can be solved. 

The answer to the subproblemis then integrated with the solution to the original problem to create the solution. 

Merge sort has an O(n* log n) time complexity.

The process of anticipative multitasking allows computer programs to share operating systems (OS) and hardware resources. It switches resources across processes based on predefined parameters and allocates operating and processing time among them. Time-shared multitasking is another term for preemptive multitasking.

The fill factor specifies how much space will be given to data on each leaf-level page. The page, which is made up of 8K pages, is the smallest unit in SQL Server. The number of rows per page is determined by the row size. 

Fill Factor's default value is 100, which is the same as the number 0. When the Fill Factor is set to 100 or 0, SQL Server will try to fill the index's leaf-level pages with as many rows as feasible. When the fill factor is 100, there will be no or very little vacant space on the page. 

No employer wants a candidate who will depart the firm after only a few years. They predict that the applicants will be a strong match for the organization over the next 7-8 years. Even if you are doubtful, you must assure them that as long as the job you perform challenges you and contributes to a thriving firm, it will help you grow.  

These are some Cognizant interview questions that you shouldn’t skip. 

The C compilation process begins with the pre-processing of a source file. A pre-processor is a tiny piece of software that receives a C source file and performs the functions listed below.

• Remove comments from the original code.
• Macro expansion.
• Expansion of included header files.

It creates a temporary file with the extension.i after pre-processing. Because it adds the contents of header files to our source code file. The pre-processor produced file is bigger than the original source file.