Chetu Software Engineer Interview Questions and Answers

Joins in SQL combine rows from two or more tables based on related columns.

• INNER JOIN: Returns records with matching values in both tables. Example: SELECT * FROM A INNER JOIN B ON A.id = B.id;

• LEFT JOIN: Returns all records from the left table and matched records from the right table. Example: SELECT * FROM A LEFT JOIN B ON A.id = B.id;

• RIGHT JOIN: Returns all records from the right table and matched records from t...read more

Print and echo are both used to output data in PHP, but they have key differences in usage and behavior.

• echo can take multiple parameters: echo 'Hello', 'World';

• print can only take one argument: print 'Hello World';

• echo is slightly faster than print because it doesn't return a value;

• print returns 1, so it can be used in expressions: $result = print 'Hello';

• echo does not require parentheses: echo 'Hello'; while pri...read more

Reverse a string in C# without using built-in features

• Create a character array from the input string

• Use two pointers to swap characters at the beginning and end of the array

• Continue swapping until the pointers meet in the middle

foreach is used to iterate over an array and perform an action on each element, while map creates a new array by applying a function to each element of an existing array.

• foreach does not return a new array, while map does

• foreach can only perform an action on each element, while map can transform each element

• foreach is useful for performing side effects, while map is useful for creating a new array with transformed...read more

Routing is used to direct network traffic efficiently and securely.

• Routing helps to find the best path for data packets to travel.

• It enables load balancing and fault tolerance.

• Routing protocols like OSPF, BGP, and EIGRP are used to manage routing tables.

• Routing can be static or dynamic depending on the network requirements.

Abstract classes are classes that cannot be instantiated and can have both abstract and non-abstract methods. Interfaces are contracts that define methods that must be implemented by a class.

• Abstract classes can have constructors while interfaces cannot

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

• Abstract classes can have instance variables while interfaces cannot

• Interfaces...read more