Understanding Programming Concepts

What are the basic data types in JavaScript?

• Array

• Function

• Object

• Undefined, Null, Boolean, Number, BigInt, String, Symbol

Explain the difference between == and === operators.

• The '==' operator is for loose equality, and the '===' operator is for strict equality.

• The '==' operator checks data types, while '===' does not.

• Both '==' and '===' are used for strict equality comparison.

• The '===' operator is used for loose equality, while '==' is for strict equality.

What is a conditional statement? Give an example.

• If the sun shines, then it will rain.

• If it rains, then the ground will be wet.

• If I study hard, then I will fail the exam.

• If it snows, then the ground will be dry.

Describe a for loop and its syntax.

• for (start; check; update) { // execute code }

• for (i = 0; i < n; i++) // loop body

• for each (item in collection) { // process item }

• for (initialization; condition; increment) { // code to execute }

What is an array and how is it different from an object?

• An array is a collection of key-value pairs, while an object is an ordered collection of items.

• An array is a single value, while an object is a list of values.

• An array can only contain numbers, whereas an object can contain any data type.

• An array is an ordered collection of items, while an object is a collection of key-value pairs.

How do you access an element in an array?

• Access elements using arrayName[index + 1].

• Use arrayName.get(index) to access an element.

• You can retrieve an element with arrayName.fetch(index).

• Use arrayName[index] to access an element.

What is a string in programming? How can you manipulate it?

• A string is a type of variable that cannot be changed once created.

• A string is a numeric value; it can only be added or subtracted.

• A string is a collection of functions used for data analysis.

• A string is a sequence of characters; it can be manipulated through operations like concatenation, slicing, searching, replacing, and transforming.

Define a function and its purpose in programming.

• A function is a type of variable that stores data.

• A function is a reusable block of code that performs a specific task.

• A function is a graphical representation of code execution.

• A function is a method to compile programming languages.

What is a callback function? Provide an example.

• An example of a callback function is: function add(a, b) { return a + b; }

• A callback function is a function that is executed immediately without any parameters.

• An example of a callback function is: function fetchData(callback) { fetch('url').then(response => response.json()).then(data => callback(data)); }

• A callback function is a function that runs in parallel with another function.

How do you declare a variable in JavaScript?

• You declare a variable using 'var', 'let', or 'const'.

• You declare a variable using 'assign'.

• You declare a variable using 'define'.

• You declare a variable with 'set'.