1000+ Software Engineer Interview Questions and Answers for Freshers

Design algorithm and database for seat booking system of BookMyShow and handle failed payments.

• Create a database with tables for movies, theaters, seats, bookings, and payments

• Use a locking mechanism to prevent double booking of seats

• If payment fails, release the locked seats and notify the user

• Write a query to get the timestamp in SQL: SELECT CURRENT_TIMESTAMP;

Other than indexes and tables, a DBMS also includes views, stored procedures, triggers, and functions.

• Views: Virtual tables that are based on the result of a query. They provide a way to simplify complex queries and restrict access to data.

• Stored Procedures: Precompiled sets of SQL statements that can be executed with a single command. They enhance performance and allow for code reusability.

• Triggers: Special types of stored procedures that are automatically executed when a sp...read more

SDLC is a process followed by software development teams to design, develop and test high-quality software.

• SDLC stands for Software Development Life Cycle

• It consists of several phases including planning, analysis, design, implementation, testing, and maintenance

• Each phase has its own set of activities and deliverables

• The goal of SDLC is to produce high-quality software that meets customer requirements and is delivered on time and within budget

• Examples of SDLC models include W...read more

Virtual memory is a memory management technique that allows the operating system to use a combination of RAM and hard disk space.

• Virtual memory is a way for the operating system to provide more memory to applications than what is physically available in RAM.

• It creates an illusion of a larger memory space by using a portion of the hard disk as an extension of RAM.

• Virtual memory allows multiple processes to run simultaneously without the need for physical memory to accommodate ...read more

The padding size for the last member of a struct is determined by the alignment requirements of the struct.

• Padding is added to ensure that each member of the struct is properly aligned in memory.

• The padding size depends on the size and alignment requirements of the previous members.

• The compiler may also consider the target architecture and optimization settings when determining padding size.

Program for login page with session and palindrome program

• Create a login page with HTML and CSS

• Use PHP to handle form submission and validate user credentials

• Create a session for the logged-in user

• Design a database to store user information

• Write a program to check if a given string is a palindrome

Sorting techniques and their time complexity

• Bubble sort - O(n^2)

• Selection sort - O(n^2)

• Insertion sort - O(n^2)

• Merge sort - O(n log n)

• Quick sort - O(n log n)

• Heap sort - O(n log n)

• Radix sort - O(nk)

• Most efficient: Quick sort or Merge sort

• Efficiency depends on the size of the array and the data distribution

The set of all nodes that can occur in any path from a source to a destination in both directed and undirected graphs.

• Perform a depth-first search (DFS) or breadth-first search (BFS) from the source node to the destination node.

• During the search, keep track of all visited nodes.

• Add each visited node to the set of nodes that can occur in any path.

• Repeat the search for both directed and undirected graphs.

• The resulting set will contain all nodes that can occur in any path from t...read more

Sorting an array of infinite length with only three elements (-1, 0, 1)

• Use counting sort algorithm to count the frequency of each element

• Create a new array with sorted elements based on their frequency

• Time complexity is O(n) and space complexity is O(1)

• Example: [-1, 1, 0, 1, -1, 0, 1, -1, 0, 1, ...]

C is a procedural programming language while C++ is an object-oriented programming language.

• C is a procedural programming language, meaning it focuses on procedures or functions.

• C++ is an extension of C and adds object-oriented features like classes and inheritance.

• C++ supports polymorphism, encapsulation, and abstraction, which C lacks.

• C++ allows the use of standard template library (STL) for data structures and algorithms.

• C++ has exception handling mechanisms, whereas C doe...read more

The size of the structure is 12 bytes. The members will be allocated memory based on their data types.

• The structure 'abc' has three members: 'a' of type int, 'b' of type int, and 'c' of type char.

• The size of int is typically 4 bytes and the size of char is typically 1 byte.

• The total size of the structure is calculated by summing the sizes of its members.

• In this case, 4 bytes for 'a', 4 bytes for 'b', and 1 byte for 'c', resulting in a total of 12 bytes.

• The members will be all...read more

To add a new column to an existing table, use the ALTER TABLE command.

• Use the ALTER TABLE command followed by the table name.

• Use the ADD keyword followed by the new column name and its data type.

• Example: ALTER TABLE table_name ADD column_name data_type;

• Make sure to specify any additional constraints or default values for the new column.

Yes, we can pass arguments in place of args in string[] args.

• Arguments can be passed directly as an array of strings.

• The number of arguments passed must match the size of the array.

• Example: public static void main(String[] args) can be called as main(new String[] {"arg1", "arg2"});

Manhole covers are round because they cannot fall through the hole they cover and are easier to move.

• Round covers cannot fall through the hole they cover, unlike square covers which can fall diagonally.

• Round covers are easier to move as they can be rolled instead of lifted.

• Round covers are also more aesthetically pleasing and symmetrical.

• Square covers may also have sharp corners which can be dangerous to pedestrians and vehicles.

Yes, I am comfortable using both CLIs and IDEs for my daily tasks.

• I have experience using various CLIs such as Git Bash, Windows Command Prompt, and Terminal on macOS.

• I am proficient in using IDEs such as Visual Studio Code, Eclipse, and IntelliJ IDEA.

• I understand the benefits and drawbacks of both CLIs and IDEs and can choose the appropriate tool for the task at hand.

Keys in a database are unique identifiers used to establish relationships between tables and ensure data integrity.

• Keys are used to uniquely identify records in a database table.

• Primary keys are used to uniquely identify each record in a table.

• Foreign keys establish relationships between tables.

• Keys help enforce data integrity and maintain consistency in the database.

• Examples of keys include primary keys, foreign keys, and unique keys.

Data structures are a way to organize and store data efficiently.

• Data structures are used to store and manipulate data in a structured manner.

• They provide different ways to access and perform operations on the data.

• Examples include arrays, linked lists, stacks, queues, trees, and graphs.

Find the element that occurs only once in an array of numbers from 1 to n with all other numbers occurring twice.

• Use XOR operation to find the unique element.

• Iterate through the array and XOR each element with the result.

• The final result will be the unique element.

Find the maximum interval that intersects the maximum number of intervals.

• Sort the intervals based on their start times.

• Iterate through the sorted intervals and keep track of the current interval with the maximum number of intersections.

• Update the maximum interval whenever a new interval intersects more intervals than the current maximum interval.

Indexes are used to improve query performance. Multiple clustered and non-clustered indexes can be created on a table.

• Indexes are used to quickly locate data without scanning the entire table.

• Clustered index determines the physical order of data in a table.

• Non-clustered index is a separate structure that contains a copy of the indexed columns and a pointer to the actual data.

• A table can have only one clustered index, but multiple non-clustered indexes.

• Indexes should be create...read more

You cannot take 4 liters from a 2 liter and 5 liter jugs.

• It is not possible to take 4 liters from a 2 liter and 5 liter jugs.

• The combined capacity of the two jugs is less than 4 liters.

• You would need a larger jug or a different approach to obtain 4 liters.

The throw() statement is internally implemented by creating an exception object and transferring control to the catch() block.

• When a throw() statement is executed, an exception object is created.

• The exception object contains information about the type of exception and any additional data.

• The control is then transferred to the nearest catch() block that can handle the exception.

• The catch() block can access the exception object and perform appropriate actions.

• If no catch() bloc...read more

Static and global variables have different scopes and lifetimes depending on where they are declared.

• Static variables declared inside a function retain their value between function calls.

• Static variables declared outside any function have file scope and are accessible within the file.

• Global variables have global scope and can be accessed from any part of the program.

• Global variables are initialized only once and retain their value throughout the program execution.

Adding two numbers represented as linked lists with different lengths.

• Traverse both linked lists simultaneously, adding corresponding digits and carrying over the carry.

• If one list is shorter, consider the remaining digits as 0.

• Create a new linked list to store the result.

• Handle the case when the sum of digits exceeds 9 by carrying over the digit to the next place value.

• If there is a carry after adding all digits, add an additional node to the result linked list.

A program to convert binary to decimal and decimal to binary.

• For binary to decimal conversion, iterate through each digit of the binary number and multiply it by 2 raised to the power of its position.

• For decimal to binary conversion, repeatedly divide the decimal number by 2 and keep track of the remainders.

• Use the modulo operator (%) to get the remainder and the division operator (/) to get the quotient.

Abstraction is a way of hiding implementation details and showing only necessary information to the user.

• Abstract class is a class that cannot be instantiated and can have both abstract and non-abstract methods.

• Interface is a collection of abstract methods and constants that can be implemented by any class.

• Abstract classes can have constructors, while interfaces cannot.

• A class can implement multiple interfaces, but can only inherit from one abstract class.

• Abstraction helps in...read more

Constructor and destructor are special member functions in a class that are used to initialize and destroy objects respectively.

• Constructor is called when an object is created and is used to initialize the object's data members.

• Destructor is called when an object is destroyed and is used to free up any resources allocated by the object.

• Constructor has the same name as the class and no return type, while destructor has the same name as the class preceded by a tilde (~) and no ...read more

Create dynamic buttons with JSON data, maintain active/inactive states, and show content on click

• Create buttons dynamically using JSON data

• Toggle between active and inactive states on click

• Display button content based on JSON data on click

By providing self-service options and resources, such as FAQs and online documentation.

• Create a comprehensive FAQ section on the company's website

• Develop an online knowledge base with step-by-step guides and troubleshooting tips

• Offer live chat support with automated responses and chatbots

• Provide video tutorials and instructional videos

• Implement a community forum where customers can help each other

I know multiple programming languages.

• I am proficient in Java, Python, and C++.

• I have experience with web development languages such as HTML, CSS, and JavaScript.

• I am familiar with scripting languages like Bash and PowerShell.

• I have worked with database query languages like SQL.

• I have knowledge of mobile app development languages like Swift and Kotlin.

To eliminate repeated array from a given string

• Convert the string to an array using split() method

• Use Set object to remove duplicates from the array

• Convert the array back to string using join() method

Questions related to OOPS concepts in software engineering.

• Method overloading is having multiple methods with the same name but different parameters, while method overriding is having a method in a subclass with the same name and parameters as a method in its superclass.

• Inheritance is the ability of a class to inherit properties and methods from its parent class. It allows for code reuse and promotes modularity.

• Encapsulation is the practice of hiding the internal details of a...read more

BST is a binary tree where left child is smaller and right child is greater. Add/delete ops maintain this property.

• BST is a data structure used for searching, sorting, and storing data

• Add operation: Traverse the tree and find the appropriate position to insert the new node

• Delete operation: Find the node to be deleted, replace it with its inorder successor or predecessor, and delete the successor/predecessor node

• Time complexity: O(log n) for both add and delete operations

• Code ...read more

Print a string with all occurrences of the first character first.

• Loop through the string and count the occurrences of the first character.

• Print the first character that many times, then print the rest of the string.

ACID properties ensure database transactions are reliable. Two transactions can occur simultaneously using locking and isolation.

• ACID stands for Atomicity, Consistency, Isolation, and Durability.

• Atomicity ensures that a transaction is treated as a single unit of work, either all or none of it is executed.

• Consistency ensures that a transaction brings the database from one valid state to another.

• Isolation ensures that concurrent transactions do not interfere with each other.

• Dur...read more

Set is a collection interface in Java. HashSet and HashMap are two different implementations of Set.

• Set is an interface that extends Collection interface.

• HashSet is an implementation of Set that uses a hash table to store elements.

• HashMap is an implementation of Map that uses a hash table to store key-value pairs.

• HashSet does not allow duplicate elements while HashMap allows duplicate values but not duplicate keys.

• HashSet uses only one object to store elements while HashMap u...read more

Merge two sorted arrays with empty spaces at the end in a single pass.

• Initialize two pointers at the end of each array

• Compare the elements at the pointers and place the larger element at the end of the merged array

• Decrement the pointer of the array from which the larger element was taken

• Repeat until all elements are merged

A queue can be implemented using a stack by using two stacks and simulating the enqueue and dequeue operations.

• Create two stacks, stack1 and stack2.

• For enqueue operation, push the element onto stack1.

• For dequeue operation, if stack2 is empty, pop all elements from stack1 and push them onto stack2. Then pop the top element from stack2.

• This ensures that the first element pushed onto stack1 is the first element to be popped from stack2, simulating a queue.

The question is about synchronizing two threads to print odd and even numbers from 1 to 10.

• Use synchronization mechanisms like locks or semaphores to ensure only one thread prints at a time

• Create two separate functions for printing odd and even numbers

• Use a shared variable to keep track of the current number being printed

• Use a loop to iterate from 1 to 10 and call the appropriate function based on the current number

Program to swap two numbers without using third variable

• Use the XOR operation to swap the numbers

• Assign the first number to the second number using XOR

• Assign the second number to the first number using XOR

Deadlocks are situations where two or more processes are unable to proceed because each is waiting for the other to release a resource.

• Deadlocks occur when multiple processes are stuck in a circular waiting state.

• Prevention techniques include resource allocation strategies, deadlock detection, and avoidance algorithms.

• Examples of prevention techniques are using a resource allocation graph, implementing a banker's algorithm, and employing timeouts and resource preemption.

We used Python 3.7 and Django 2.2 framework for the project.

• Python 3.7 was used as the programming language

• Django 2.2 was used as the web framework

• We also used other libraries and tools such as Pandas, NumPy, and Git

• The project was developed using Agile methodology

Measure x gallons of water using 4 and 7 gallon jugs.

• Fill 7 gallon jug completely

• Pour water from 7 gallon jug to 4 gallon jug until it's full

• Remaining water in 7 gallon jug = 3 gallons

• Empty 4 gallon jug and pour the 3 gallons from 7 gallon jug to 4 gallon jug

• Fill 7 gallon jug again and pour water to fill the remaining space in 4 gallon jug

• Remaining water in 7 gallon jug = x - 3 gallons

Implementing all linked list operations from scratch and reversing it.

• Start by creating a Node class with data and next pointer

• Implement insert, delete, search, and traverse operations

• To reverse the linked list, use three pointers to reverse the direction of the links

• Make sure to handle edge cases such as empty list and single node list

No, paging cannot be implemented completely in the OS without paging hardware.

• Paging is a hardware feature that allows the operating system to manage memory efficiently.

• Without paging hardware, the OS would not have the necessary mechanisms to map virtual addresses to physical addresses.

• Paging hardware includes components like the Memory Management Unit (MMU) and Translation Lookaside Buffer (TLB).

• These hardware components are responsible for translating virtual addresses to ...read more

Yes, a variable value can be assigned to a static variable during initialization.

• Static variables are initialized only once, at the start of the program.

• The value assigned to a static variable during initialization can be a constant or the result of an expression.

• The assigned value can be changed later in the program, but it will retain its value between function calls.

• Static variables are useful for preserving data across multiple function calls.