Interview Questions and Answers for 'C' | Search Interview Question

Interview Questions and Answers for 'C' - 2780 question(s) found - Order By Rating

Q1. What is Array.Map function ? What will be output of following ?

const myArray = [1, 4, 9, 16];
const result = myArray.map(x => x * 2);

Javascript

Ans. It will create an array with each value as x*2

[2, 8, 18, 32]

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Q2. What is systemd in Unix ?

Unix

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Q3. Why cannot we initialize a final field within the constructor if the initialization is within try block ?

Core Java

Ans. What if the initialization throws an exception. In that case , it will let it move forward without initializing the final field. So it's a way to enforce that either the field is initialized or it fails completely.

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Q4. Can we initialize final fields within the constructor ? Why ?

Core Java

Ans. Yes, Because final fields needs to be initialized before the construction of the object completes. Not necessarily at the time of class loading.

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Q5. Will this code give any error ?

let result: string;
result = false || 'true';

Typescript

Ans. No

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Q6. Will this code give any error ?

let result: boolean | string;
result = false || 'true';

Typescript

Ans. No

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Q7. Will this code give any error ?

let result: boolean;
result = false || true;

Typescript

Ans. No

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Q8. Will the following code give any error

let result: boolean;
result = false | true;

Typescript

Ans. Yes, | is a bitwise operator and not boolean or. Use || instead

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Q9. Will the following code give any error

let result: string | number;
result = 'true';

Typescript

Ans. No

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Q10. Will the following code give any error

let result: string | number;
result = 'true';

Typescript

Ans. No

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Q11. Will the following code give any error

let result: string | number;
result = true;

Typescript

Ans. Yes, result can either be string or a number but not boolean.

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Q12. What does the following declaration mean

let result: string | number;

Typescript

Ans. It means we can assign either a string or a number to result.

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Q13. How can we specify that a particular variable may have either of the two data types in Typescript ?

Typescript

Ans. Yes

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Q14. How can we specify that a particular variable may have either of the two data types in Typescript ?

Typescript

Ans. let result: string | boolean;

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Q15. Can we specify that a particular variable may have either of the two data types in Typescript ?

Typescript

Ans. let result: string | boolean;

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Q16. Is it safe to use session storage ?

Javascript

Ans. Session storage can be accessed from XSS (Cross site Scripting) attacks but cookies (if set with "HttpOnly" and "Secure" flags) are more safer against these attacks.

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Q17. How can you trim all strings in an array ?

Ans. array.map(s => s.trim())

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Q18. Do you ever merge changes from one feature branch to another ? Why ?

SCM

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Q19. Can we do a thread specific heap allocation ?

Memory Management

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Q20. Why do we do transformation on the observable itself rather than doing it in the subscriber ?

RxJs

Ans. Because that way we just need to do that transformation at one place and not within each subscriber. Single source of truth.

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Q21. What is the difference between Subject and Observable ?

Angular

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Q22. What is the difference between subscribe and unsubscribe ?

Angular

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Q23. What is the difference between subscribe and emit ?

Angular

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Q24. What is a pseudo-class?

CSS

Ans. It is a CSS technique that sets the style when an element changes its state. E.g. style changes when mouse hover, different styles for visited or unvisited links, etc.

There are four different types of pseudo-classes:

Links: These pseudo-classes are used to style the link both in its normal state by default and when it has already been visited
Dynamic: Dynamic pseudo-classes can be applied to any element to define how they are shown when the cursor is located on them, or by clicking on them or when they are selected
Structural: Structural pseudo-classes allow to style elements based on an exact numerical position of the element
Others: Some elements can be styled differently based on the language or what type of label they are not.
Format
Name
Elements are styled if
Compatibility
Link and Dynamic Pseudo-classes
: link   Link   the value of the href attribute is not in the history   IE4, FF1, O3.5, S1, CSS1
: visited   Link Visited   the value of the href attribute is in the history   IE4, FF1, O3.5, S1, CSS1
: target   Target Link   a targeted link   FF1.3, O9.5, S1.3, CSS3
: active   Active   the element has been clicked   IE7, FF1, O3.5, S1, CSS1
: hover   On   the cursor is over the element   IE4 *, FF1, O3.5, S1, CSS2
: focus   Focus   the element captures the focus of the document   IE7, FF1, O7, S1, CSS2
* Only available for the item before IE7
Structural and Other Pseudo-classes
: root   Root   is the main element of a document   FF1.5, O9.5, S3.1, C3, CSS3
: empty   Empty   does not have child nodes   FF1.5, O9.5, S3.1, C3, CSS3
: only-child   Only son   has no sibling nodes   FF1.5, O9.5, S3.1, C3, CSS3
: only-of-type   Type Only   has a unique selector among its siblings   FF1.5, O9.5, S3.1, C3, CSS3
: first-child   First son   is the first child node of another element   FF1.5, O9.5, S3.1, C3, CSS3
: nth-of-type (n)   Nth of Type   is the nth element with that selector   FF1.5, O9.5, S3.1, C3, CSS3
: last-child   Last son   is the last child node of an element   FF1.5, O9.5, S3.1, C3, CSS3
: first-of-type   First of the Kind   is the first element of its selector type in the parent element   FF1.5, O9.5, S3.1, C3, CSS3
: last-of-type   Last of the Type   is the last element of its selector type in the parent element   FF1.5, O9.5, S3.1, C3, CSS3
: lang   Language   has a specifically defined language code   IE8, FF1.5, O9.5, S3.1, C3, CSS2.1
: not   Denial   you are not using a specific selector   FF1.5, O9.5, S3.1, C3, CSS3

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Q25. What are the main features of Java?

Core Java

Ans. a) Object Oriented
b) Simple
c) Platform Independent
d) Secured
e) Robust
f) Portable
g) Multithreaded
h) Distributed

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Q26. What are the fundamental principles of object oriented programming? / What are the OOPs concepts?

Core Java

Ans. a) Inheritance
b) Abstraction
c) Polymorphism
d) Encapsulation

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Q27. What do you mean by inheritance in java?

Core Java

Ans. Inheritance is one of the key principle of object oriented programming. Through inheritance, one class can inherit the properties of another class. The class from which properties are inherited is called super class and the class to which properties are inherited is called sub class.

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Q28. Which one of AWS Lambda or API Gateway is a compute service ?

Amazon Web Services (AWS)

Ans. AWS Lambda

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Q29. How can print the whole object state in the console in javascript ?

Javascript

Ans. We can JSON.stringify

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Q30. What are the differences between static and non-static methods?

Core Java

Ans. Static method is common to all instances of a class. Static methods are stored in the class memory. Whereas non-static methods are stored in the object memory. Each instance of a class will have their own copy of non-static methods.

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