Infosys

Question 1

Difference between REST and SOAP

Answer 1

REST is Synchronous uses XML, Json, Plain Text, etc., transfer over HTTP, Javascript support is easy, calls services using HTTP request, uses XML AND JSON to send and receive data. Business logic is URIs Also, no error handling. Example of REST documentation is Swagger. Emphasizes stateless communication
SOAP is Asynchronous, uses only XML well documented but has many options with respect to documentation that can be difficult to understand, error handling is built in, transfers over HTTP, SMTP, FTP etc., its business logic is services interfaces. Supports stateless and stateful operations

Question 2

Default class & default member

Answer 2

class= internal

member=private

Question 3

What is REST?

Answer 3

Rest stands for Representational State Transfer. It tells you how you should transfer information and communicate with the client. An architectural style that uses Service Oriented Architecture; Restful service pertains to creating a web service. It is compatible with http(s) protocols & can use any messaging format such as .json, xml or a custom format. Its lightweight and consumes less bandwidth

Question 4

What is AJAX and have you used it in a project before?

Answer 4

Asynchronous JS and XML
Used to grab information only with XML type backend server hence the name
But now updated for the object to also include JSON to be relevant
**This is how we send request and fetch API

Question 5

What is routing?

Answer 5

[Route(“[controller]”)]
the middleman between the asp.net and the client and handles the http responses and routes the information back to the client

Helps ASP.Net to route the user’s http request for example which controller and which action inside of the controller routing where the http request should go to.
The routing middleware is used to find the appropriate controller and action in the controller to handle the request

Question 6

Http Life Cycle

Answer 6

Your browser (the client) will send a request (the url you sent)
The server will receive that request & do some processes
Server will send a response (html, css, json, js etc)
Client will receive response for browser to process the response

Question 7

What is the HTTP response codes?

Answer 7

1xx Informational 
2xx Successful status
3xx Redirection
4xx Client errors
5xx Server errors

Question 8

Http methods (what they do)

Answer 8

GET: request data,
POST: sends data to server (HTML)
PUT: creates a new resource or replaces
DELETE: delete request

Question 9

What are abstract methods?

Answer 9

~implicitly a virtual method.
~declarations are only permitted in abstract classes
~abstract method declaration provides no actual implementation,
~there is no method body, the method declaration
~ simply ends with a semicolon and there are NO curly braces { } following the signature.

Question 10

What is Interface?

Answer 10

Complier enforces contracts, & all methods are public abstract, variables are public, static, or final (declaring behaviors for objects)
An interface describes what behaviors (verb) A class should have; it provides none of its own

Question 11

What is a constructor?

Answer 11

is used to initialize the state of an object.
not required to have a return type.
is invoked implicitly.
The compiler provides a default constructor if you don’t have any constructor in a class.
The constructor’s name must be same as the class name.
5 types: Default, Copy, Parameterized, Copy, Static, Private

Question 12

Give the syntax for attribute routing

Answer 12

The general syntax is {parameter:constraint}
Ex:
[Route(“customers/{customerId}/orders/{orderId}”)]
public Order GetOrderByCustomer(int customerId, int orderId) { … }

Question 13

Connection differences between ADO.NET and Entity Framework

Answer 13

ADO.Net is directly connected to the data source and gives better performance, entity framework translates the LINQ queries to SQL first and then process the query

Question 14

How do you connect API to the database?

Answer 14

Through a connection string in our azure server

Question 15

What is authentication and authorization

Answer 15

Authentication is checking the identity and authorization is the permission levels of access

Question 16

What are SOLID principles?

Answer 16

Enables us to manage most of the software design problems, intended to make software designs more understandable
Single Responsibility:
Open Closed Principle
Liskov Substitution Principle
Interface Segregation Principle
Dependency Inversion Principle

Question 17

SOLID concepts

Answer 17

A class should have only one reason to change, and the responsibility should be encapsulated by the class
	Open for extension closed for modification means to allow new functionality with minimal changes to existing code 
	Objects are replaceable with instances of subtypes without altering the correctness of the program
	Separate multiple interfaces are better than one shouldn’t enforce clients to implement interfaces they don’t use 
	Higher level modules shouldn’t depend on low level modules

Question 18

OOP Pillars

Answer 18

Encapsulation - Wrapping up of the data & data hiding, with use of access modifiers to provide levels of access
Abstraction - Showing only essential features of the program instead on un-necessary details.
Inheritance - Is a way to extend a type so that its properties and behaviors can be extended/branched further.
Polymorphism- Ability to implement inherited properties or methods in different ways across multiple abstractions.
Static/Compile time polymorphism or Dynamic/Runtime polymorphism.

Question 19

OOP Advantages

Answer 19

~OOPs makes development and maintenance easier whereas in a procedure-oriented programming language it is not easy to manage if code grows as project size increases.
~OOPs provides data hiding whereas in a procedure-oriented programming language a global data can be accessed from anywhere.

Question 20

What is a constructor?

Answer 20

5 types: Default, Copy, Parameterized, Copy, Static, Private
is used to initialize the state of an object.
not required to have a return type.
is invoked implicitly.
The Java compiler provides a default constructor if you don’t have any constructor in a class.
The constructor’s name must be same as the class name.

Question 21

What is Interface?

Answer 21

Complier enforces contracts, & all methods are public abstract, variables are public, static, or final (declaring behaviors for objects)
An interface describes what behaviors (verb) A class should have; it provides none of its own

Question 22

What are abstract methods?

Answer 22

~implicitly a virtual method.
~declarations are only permitted in abstract classes
~abstract method declaration provides no actual implementation,
~there is no method body, the method declaration
~ simply ends with a semicolon and there are NO curly braces { } following the signature.

Question 23

Http methods (what they do)

Answer 23

GET: request data,
POST: sends data to server (HTML)
PUT: creates a new resource or replaces
DELETE: delete request

Question 24

Give the syntax for attribute routing

Answer 24

The general syntax is {parameter:constraint}
Ex:
[Route(“customers/{customerId}/orders/{orderId}”)]
public Order GetOrderByCustomer(int customerId, int orderId) { … }

Question 25

What is method overloading and overriding?

Answer 25

``` ~Method overriding is an example of runtime polymorphism, ~Redefining the method of the parent class into the child class. ~To override the method in the parent class, in child class you need to specify a method of the same signature ~necessary to make a method overridable by using abstract or virtual keyword in base class ~In child class use the keyword override to override these methods. ```

Question 26

What is method overloading and overriding?

Answer 26

Overloading ~Method overloading is an example of static/compile time polymorphism ~Creation of methods with the same name as another in the same class, nut differs in parameters (order number, type) ~Methods with the same name behaves differently based on signatures(parameters):

Question 27

What is singleton

Answer 27

A single constructor is private and parameter less. This prevents other classes from instantiating it

Question 28

What is a sealed class in C#?

Answer 28

The sealed modifier prevents other classes from inheriting from it.

Question 29

What is test driven development?

Answer 29

software development process used to test cases before software is fully developed and track software development by repeatedly testing the software against all test cases. - Mantra: Red, Green, Refactor - Structure: Arrange, Act, Assert

Question 30

How would you write a unit test?

Answer 30

[ Test ] Triple A’ Arrange: initializes object and set values of data passed to the method Act: invokes the method, testing the arranged parameters Assert: verifies the action does what it’s supposed to do

Question 31

What is JSON?

Answer 31

Javascript object notation is a readable language for users in a data-interchange

Question 32

Code Coverage

Answer 32

It is the percentage given to you on how much lines of your code are covered by unit testing

Question 33

Static

Answer 33

``` A non-access modifier determines if the method or variable belongs to a class as a whole or as an instance. Methods and variables labeled static without the need to create an object of the class, but the main method is always labeled A static method can not be overridden because it pertains to the class not the object, and the static method can be called without the class instance ```

Question 34

Do you have any experience with LINQ to ADO.Net

Answer 34

It is a query language that is very similar to our SQL useful for filtering/acquiring/aggregating data Method syntax- use methods to perform the queries (simple queries) Query syntax- more like SQL in that you create a statement-like operation using keywords (joins)

Question 35

Agile:

Answer 35

Give the client what they want with little to no documentation, an Asynchronous, automatic development/ deployment cycle

Question 36

How would you use a connection string without hard coding it into your program?

Answer 36

Some type of secret key or a configuration manager System.Configuration

Question 37

How to achieve multiple inheritance in c#

Answer 37

Multiple inheritance in C#( not allowed)

Question 38

Model Binding

Answer 38

It is a way to bind data (JSON objects) coming from HTTP request to be automatically mapped into a C# model Model Binder looks for those values in different ways: o QueryString -> Primitive types o Request Body -> Complex Types Just like HTTP transfers information by JSON files. ASP.NET automatically maps the JSON object into a C# object and vise-versa

Question 39

.NET & C# | What is MVC. (Model View Controller)

Answer 39

used to implement user interfaces, data, and controlling logic. Used to decouple where to or more systems work/connect without direct connectivity, uses a buffer to separate the fetch and decode stages from the execution stage

Question 40

What is Entity Framework

Answer 40

An open source ORM, object relational mapping for .NET | defines context classes and entity classes that make up a model and uses migrations to create a database

Question 41

ADO.NET and ASP.NET

Answer 41

ASP.NET is the compiled language. ASP uses ADO (ActiveX Data Objects) technology to connect and work with databases. ASP.NET uses ADO.NET to connect and work with databases. ASP is partially object-oriented. ADO.NET uses Microsofft.Data.Sqlclient

Question 42

What is a DLL?

Answer 42

Dynamic link library contains code and data that can be used by more than one program at the same time

Question 43

What is Truncate and Delete commands in SQL?

Answer 43

Are Data Definition Languages Truncate command (Keeps table removes records from table) removes all rows/records from a table, without logging individual row deletions, Delete: deletes the whole table unless specified

Question 44

What do you know about normalization?

Answer 44

Organizing data in database reducing redundancy, improve referential integrity to read/write with consistency remove insertion, update, and deletion anomalies. 1NF~ columns should be atomic, no multiple values, separated by a comma. Table doesn’t contain repeating column groups Identify each record uniquely using primary key 2NF~all conditions of 1NF, move redundant data to separate table Create relationship between these tables using foreign keys 3NF-meets all conditions of 1NF & 2NF Does not contain columns(attributes) that are not fully dependent upon the primary

Question 45

How would you connect the API to a sql database?

Answer 45

Using the connection string from the server in my data logic or repository

Question 46

What are some datatypes in SQL?

Answer 46

``` Numeric, whole numbers, floating, currency, Boolean String/Text (string): Char- fixed length non-Unicode Varchar-variable length up to (n) non-Unicode NCHAR-fixed Unicode NVARCHAR- variable length Unicode Date/time ```

Question 47

Give us some examples of query commands.

Answer 47

SELECT *, FROM, WHERE,ALTER TABLE, ADD, AND, AS

Question 48

Store procedure

Answer 48

SQL statements which are saved and stored in a RDBMS, to be reused over and over again

Question 49

A function

Answer 49

a set of SQL statements that perform a specific task

Question 50

How would you select a unique record?

Answer 50

Use the Information Schema or select*distinct

Question 51

What are directives in angular?

Answer 51

the middleman between the asp.net and the client and handles the http responses and routes the information back to the client Helps ASP.Net to route the user’s http request for example which controller and which action inside of the controller should the http request go to. The routing middleware is used to find the appropriate controller and action in the controller to handle the request

Question 52

Purpose of Routing Module

Answer 52

Route the traffic, ngModule configure the routes, its destination usually in src and in the app to set up the root of the application Its meta data is: Declarations list of components Imports list of modules used by component templates Providers list of service providers Bootstrap contains the root component

Question 53

Component decorator:

Answer 53

``` selector: a css selector that tells angular to create and insert an instance of this component into a specified element templateUrl: the module relative address to the components' HTML template, or an inline HTML template styleUrls: an array of css files or inline css styles ```

Question 54

What are some angular directives?

Answer 54

are markers on a DOM element that tells Angular to change the appearance, behavior, and/or layout of the Dom element and its children

Question 55

Structural Directives

Answer 55

Change the DOM layout by adding and removing DOM elements ngIf: allows us to add or remove DOM elements based upon a Boolean expression • you can also add an #elseBlock ngFor: allows us to repeat a part of the HTML template once per each item from an iterable list ngSwitch: allows us to switch between different elements depending on the expression. It is used with the following directives • ngSwitchCase • ngSwitchDefault

Question 56

Attribute Directives

Answer 56

Attribute Directives are used to change the look and behavior of the DOM element • ngClass: used for adding or removing CSS classes on an HTML element. It can allow us to apply CSS classes dynamically based on expression evaluation • ngStyle: allows you to dynamically change the style of an HTML element based on an expression • ngModel-invokes 2-way data binding

Question 57

What is the difference between let and var?

Answer 57

Let limits the scope of the variable depending on where it was declared mostly use ‘let’ to avoid conflicting name variables Var keyword that will give variable a global scope

Question 58

What does ng Bind?

Answer 58

Data Binding provides communication between a component and the document object model (DOM) 1-way allows us to manipulate views through models through: ~String interpolation binds data from a typescript class to a template using the {{}} ~Property binding allows to bind values to attributes of HTML elements ~Event binding binds DOM events (keystrokes, buttons, click, etc. to a function in the component 2-way a way to reflect changes in the template and component ~Achieved by combining property binding and event binding ~Gather user input

Question 59

``` In angular to inject services into a component of the application Allows a class to receive dependencies from an outside source Helps to loosely couple our code ```

Answer 59

``` In angular to inject services into a component of the application Allows a class to receive dependencies from an outside source Helps to loosely couple our code ```

Question 60

What is the difference between a directive and a component?

Answer 60

Components are the building blocks we use to break up the UI and logic. The directives are the middleman that handles the http routes and responses

Question 61

Component decorator:

Answer 61

``` selector: a css selector that tells angular to create and insert an instance of this component into a specified element templateUrl: the module relative address to the components' HTML template, or an inline HTML template styleUrls: an array of css files or inline css styles ```

Question 62

Write out a HTTP request from angular that would connect to your API

Answer 62

I would use the HTTP Client | this.http.post()

Question 63

What are Decorators and Observables?

Answer 63

Decorators: Class, Method, Property, Parameter, Accessor Observables are used for asynchronous operations: AJAX request and responses, and/or Router & Forms modules make use of observables to listen for and respond to user input events

Question 64

JavaScript Types

Answer 64

``` Boolean Null Undefined Number BigInt String Symbol ```

Question 65

How do you style a selector in CSS file?

Answer 65

``` selects specific or group HTML elements the basic ones include: ☆Element selector - When you want to select multiple elements of the same tag ☆Class selector - When you want to select multiple elements of different tags by using the class attribute ☆Id selector - When you want to select one (mostly) or a couple elements using the id attribute ```

Question 66

Difference between Composite key, Primary key and Foreign key

Answer 66

Composite key can be defined and combined with multiple columns Primary Key assigned to an id (primary identifier Foreign serves as connector between data/tables and can me couples with a primary key

Question 67

Monolithic

Answer 67

the frontend and backend tightly coupled so if I make changes to frontend, it will break the code in the backend

Question 68

Sprint

Answer 68

Intervals of work daily stand ups; specify what you’re doing before next standup, we go over blockers

Question 69

Docker file

Answer 69

Docker file contains instructions including keywords FOR, FROM, for your containerizations, its sensitive content AND COMMANDS AND USE DOCKER IGNORE

Question 70

DevOps cycles

Answer 70

TRIGGERS: set up process automated actions for continuous development JOBS: consist of the actual work STEPS: operations of the jobs to complete APPROVAL: makes sure everything is completed

Question 71

Falsey Value

Answer 71

FUN0NE

Question 72

Modules

Answer 72

are group of related components and serve same function and can be combined with other modules

Question 73

Components

Answer 73

building blocks of the application and a subset of directives

Question 74

Npm:

Answer 74

node package manager default package management for JS; consists of 3 components Website: discovers packages and manages access to public/private packages CLI: runs from terminal allowing interaction to npm Registry: public database of JS packages

Question 75

Interface

Answer 75

is a contract legally binding between the developer who is creating the class and the consumer using the class; better control on impact analysis, changing management and breaking changes Cannot write any logic in interfaces only signatures All methods, properties/fields, methods/functions are public can change by multiple inheritances (helps to add new methods without affecting the old interfaces

Question 76

TRUE OR FALSE: | NO MULTIPLE INHERITANCE WITH ABSTRACT CLASS OR SIMPLE CLASS ONLY WITH AN INTERFACE

Answer 76

TRUE

Question 77

Interface segregation principle

Answer 77

``` Do not force the client to use unnecessary methods they are not interested to use Difference between interface and an abstract class An interface can only inherit from another interface it cannot inherit from abstract class whereas an abstract class can inherit from another abstract class and an interface. ```

Question 78

Microservices

Answer 78

a variant of the service-oriented architecture structural style – arranges an application as a collection of loosely-coupled services. In a microservices architecture, services are fine-grained and the protocols are lightweight.

Question 79

Custom operator overloading

Answer 79

uses the operator keyword with static polymorphism

Question 80

Abstract classes

Answer 80

``` are partially defined parent class: They are half defined classes where some implementations are defined, and some implementations are left to the child class to be defined ```

Question 81

Abstract methods of an abstract class

Answer 81

``` are by default virtual: Define in a parent class method as virtual in the child class you can override it You cannot create an instance of an abstract class or interface the compiler will throw an exception ```

Question 82

The difference between a simple class and an abstract class:

Answer 82

``` An abstract class is a pure half defined class A simple class is a class and to make it half defined you have to write hack logic ```

Question 83

Middleware

Answer 83

helps to execute pre-processing logic before controller is executed Authentication and Authorization (OKTA)

Question 84

Scoped

Answer 84

instantiates once per request made to server

Question 85

Polymorphism:

Answer 85

(dynamic) the ability for the object to act differently in under different conditions. Classes must inherit from the parent class Static/Compile time polymorphism METHOD OVERLOADING Method without a signature, or a method with 1 input/2 inputs Will be checked at compile time; $build Dynamic/Runtime polymorphism METHOD OVERRIDING Virtual keyword/parent child relationship

Question 86

Explain Dependency Injection

Answer 86

Practice of providing dependent objects for a class from the outside rather than the class creating the dependent objects Ex: the CustomerAPIController wants the CustDbContext object. Rather than creating it from the “new” keyword its injected into the constructor Benefits: decoupled system the caller doesn’t worry about where the object comes from

Question 87

Appsettings.json

Answer 87

json stores configuration data or configuration of the project Stored In json format (name/value) Ex: connection strings, version numbers, logging TO READ (name/values) appsettings.json file must use IConfiguration interface, belongs to the Microsoft.Extensions.Configurations namespace injected by the MVC Core Dependency injection Framework IConfiguration is provided as a parameter into the constructor of the controller (dependency injected)

Question 88

wwwroot folder

Answer 88

contains the static content like CSS, HTML, Images

Question 89

What is MVC Architecture

Answer 89

``` Model – the business logic (domain, customer class supplier class, accounts, inventory, payroll etc.) Controller – connects the controller and the view, binding layer binds the model and the view; takes user input (GET, POST, PUUT, DELETE) passes data to the view View - responsible for the look and feel of colors and positioning (HTML, CSS) passes dynamic values from the controller, uses template engines, communicates with the controller ```

Question 90

What is ASP.NET core

Answer 90

ASP.NET MVC Core is an open source . cross platform (runs on linux, mac, Microsoft) web development framework used to develop web applications created by Microsoft

Question 91

ASP.NET MVC Core (2017)

Answer 91

``` Lightweight *Cross platform/ open source *Best performance and is simplified Ready-made dependency injection Very more cloud ready Appsettings.json Built in dependency injection mechanism Good HTML control and flexibility due to razor view ```

Question 92

ASP.NET MVC 5 (2003)

Answer 92

Only compatible with windows Does not support dependency injection have to write more code Can host on cloud but not like MVC core Web.config Must use 3rd party for dependency injection Good HTML control and flexibility due to razor view

Question 93

Webforms (2003)

Answer 93

Only compatible with windows Complicated Less control of HTML

Question 94

CLI

Answer 94

runs from terminal allowing interaction to npm

Question 95

Registry:

Answer 95

public database of JS packages

Question 96

Modules

Answer 96

are group of related components and serve same function and can be combined with other modules

Question 97

Falsey Value

Answer 97

FUN0NE

Question 98

Falsey

Answer 98

Boolean equivalent

Question 99

Docker file

Answer 99

contains instructions including keywords FOR, FROM, for your containerizations, its sensitive content AND COMMANDS AND USE DOCKER IGNORE

Question 100

TRIGGERS:

Answer 100

set up process automated actions for continuous development

Question 101

JOBS

Answer 101

consist of the actual work

Question 102

STEPS

Answer 102

: operations of the jobs to complete

Question 103

APPROVAL:

Answer 103

makes sure everything is completed

Question 104

Monolithic

Answer 104

Monolithic the frontend and backend tightly coupled so if I make changes to frontend, it will break the code in the backend Monolithic centralizes the code base so its in one place and engineers can step through any part of the code when debugging User request served by a monolith do not make many calls across a network; reduces chances of network failures

Question 105

Object oriented Prog: vs Procedural oriented programming

Answer 105

OOP: Focus more on structed being separated classes, Organized into classes and accessed via objects Procedural:Focuses on what to do over how to do it

Question 106

Composite key

Answer 106

can be defined and combined with multiple columns

Question 107

Primary Key

Answer 107

assigned to an id (primary identifier)

Question 108

Foreign Key

Answer 108

serves as connector between data/tables and can me couples with a primary key

Question 109

Scalar function

Answer 109

``` based on user input and return a single value UCASE() LCASE() MID() LEN() ROUND() NOW() FORMAT() ```

Question 110

Aggregate functions

Answer 110

``` AVG() COUNT() FIRST() LAST() MAX() MIN() SUM() ```

Question 111

Attribute Routing

Answer 111

Attribute routing gives you more control over the URIs in your web API.