JavaScript Basic Programming Questions

This repository contains a collection of fundamental JavaScript programs covering various programming concepts and algorithms. Each file demonstrates a specific programming problem solution.

📁 File Structure

Number Operations

ArmstrongNo.js

Checks if a given number is an Armstrong number.

• Description: An Armstrong number is a number where the sum of its digits each raised to the power of the number of digits equals the number itself.
• Example: 153 = 1³ + 5³ + 3³ = 1 + 125 + 27 = 153
• Features:
  • Counts digits in the number
  • Calculates power of each digit
  • Compares sum with original number

Fatorial.js

Calculates the factorial of a given number.

• Description: Computes the product of all positive integers up to a given number.
• Example: 5! = 5 × 4 × 3 × 2 × 1 = 120
• Implementation: Uses a for loop to multiply numbers iteratively

primeNo.js

Checks if a given number is a prime number.

• Description: Determines whether a number is only divisible by 1 and itself.
• Implementation: Checks divisibility from 2 up to the number

strongNo.js

Checks if a given number is a Strong number.

• Description: A Strong number is a number where the sum of factorials of its digits equals the number itself.
• Example: 145 = 1! + 4! + 5! = 1 + 24 + 120 = 145
• Features:
  • Extracts each digit
  • Calculates factorial for each digit
  • Sums factorials and compares with original number

OddAandEvenNo.js

Checks if a number is even or odd.

• Description: Determines whether a number is divisible by 2 (even) or not (odd).
• Implementation: Uses modulo operator (%) to check remainder

Number Reversing

ReverseNumber.js

Reverses a given number.

• Description: Reverses the digits of a number (e.g., 123 becomes 321).
• Implementation: Uses modulo and division operations to extract and reverse digits

String Operations

ReverseString.js

Reverses a given string.

• Description: Reverses the characters in a string.
• Implementation:
  • Using for loop (iterates from end to start)
  • Using while loop (alternative approach)

palindromeString.js

Checks if a string is a palindrome.

• Description: Determines if a string reads the same forwards and backwards.
• Example: "kayak" is a palindrome
• Implementation: Reverses string and compares with original

Replace_space_Underscrores.js.js

Replaces spaces with underscores and converts to lowercase.

• Description: Converts a string with spaces to snake_case format.
• Example: "Hello World This Is Js" → "hello_world_this_is_js"
• Features:
  • Splits string by spaces
  • Converts to lowercase
  • Joins with underscores

Replace_underscores_capitalizeWords.js

Replaces underscores with spaces and capitalizes each word.

• Description: Converts snake_case to Title Case.
• Example: "hello_world_this_is_js" → "Hello World This Is Js"
• Features:
  • Splits by underscores
  • Capitalizes first letter of each word
  • Joins with spaces

count_word.js

Counts occurrences of words and characters.

• Description: Multiple counting operations:
  1. Count repeated words in a string
  2. Count words in an array of strings
  3. Count occurrence of characters in a string
  4. Count occurrences by property in an array of objects
• Examples:
  • Word count: "hello world hello" → { 'hello': 2, 'world': 1 }
  • Character count: "hello" → { 'h': 1, 'e': 1, 'l': 2, 'o': 1 }

Palindrome Operations

palindrome.js

Checks if a number is a palindrome.

• Description: Determines if a number reads the same forwards and backwards.
• Example: 121 is a palindrome number
• Implementation: Reverses the number and compares with original

Array Operations

count_repreat_no.js

Counts repeated numbers in an array.

• Description: Counts how many times each number appears in an array.
• Example: [5,5,5,5,8,8,9] → { '5': 4, '8': 2, '9': 1 }
• Implementation: Uses object to track occurrences

Find_Missing_No_from_array.js

Finds missing numbers from an array.

• Description: Identifies numbers missing from a sequence 1 to N.
• Example: Array [1,2,3,5] with count 10 → Missing: [4,6,7,8,9,10]
• Features:
  • Checks if each number from 1 to count exists in array
  • Returns array of missing numbers

Series Generation

febonacciSerires.js

Generates Fibonacci series.

• Description: Generates the Fibonacci sequence where each number is the sum of the two preceding ones.
• Sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, ...
• Implementation:
  • Using for loop
  • Using while loop

🚀 Getting Started

Prerequisites

• Node.js installed on your system

Running the Programs

Each file can be run independently using Node.js:

node filename.js

Example

node ArmstrongNo.js
# Output: 153 is Armstong No

📝 Notes

• All programs are standalone and can be executed independently
• Programs contain example input values that can be modified
• Some programs include comments explaining the logic
• Code follows basic JavaScript syntax and practices

🔧 Program Categories

1. Number Theory: Armstrong numbers, Prime numbers, Strong numbers, Factorials
2. String Manipulation: Reversing, Palindrome checking, Case conversion
3. Array Operations: Counting, Finding missing numbers
4. Series Generation: Fibonacci series
5. Basic Operations: Even/Odd checking, Number reversing

📚 Learning Objectives

These programs cover:

• Loops (for, while)
• Conditional statements (if/else)
• Array manipulation methods
• String manipulation methods
• Mathematical operations
• Object creation and manipulation
• Algorithm implementation

💡 Tips for Usage

• Modify the input variables at the top of each file to test with different values
• Use console.log outputs to understand the program flow
• Experiment with different input types to see edge cases
• Combine concepts from different files to solve more complex problems

📄 License

This repository contains basic programming examples for educational purposes.