JavaScript

let name = "Kishor";    // String

const age = 25;       // Number

let isStudent = true; // Boolean
                                        

This example demonstrates how to declare variables in JavaScript using different data types:

1. String variable: name stores text data "Kishor" using let, allowing it to be changed later
2. Number variable: age stores the numeric value 25 using const, making it unchangeable
3. Boolean variable: isStudent stores true/false value using let, which can be toggled between true/false

Key Points:

• The let keyword allows you to declare variables that can be reassigned. For example:
  let name = "Kishor";
name = "John"; // This is valid
• The const keyword is used for variables that should not be reassigned. For example:
  const age = 25;
age = 26; // This will cause an error
• Data types in JavaScript include:
  • Strings: Text data wrapped in quotes ("Kishor")
  • Numbers: Numeric values without quotes (25)
  • Booleans: true/false values
  • And others like undefined, null, objects, and arrays

Simulate It!

JavaScript

let a = 10; // First number
let b = 5; // Second number
let result = a + b; // Addition operator

This example demonstrates the use of arithmetic operators in JavaScript. Let's break down the code:

1. First, we declare a variable a and assign it the value 10
2. Then, we declare another variable b and assign it the value 5
3. Finally, we use the addition operator (+) to add these two numbers and store the result in a new variable called result

When this code runs, result will contain the value 15 (10 + 5 = 15).

Key Points:

• Arithmetic operators perform mathematical operations on numbers.
• The addition operator (+) combines two values.
• Variables must be declared using let before they can be used.
• JavaScript evaluates expressions from left to right.
• The console.log() function is used to output values to the console.

Other arithmetic operations you can try:

• result = a - b // Subtraction (will give 5)
• result = a * b // Multiplication (will give 50)
• result = a / b // Division (will give 2)
• result = a % b // Modulus (will give 0)

Simulate It!

JavaScript

let score = 85;

if (score > 90) {

    console.log("Excellent!");

} else if (score > 75) {

    console.log("Good job!");

} else {

    console.log("Keep trying!");

}

This example demonstrates how to use conditional statements in JavaScript to evaluate a student's score and provide appropriate feedback based on their performance. The code uses a variable 'score' set to 85 and implements a grading system using if-else statements to determine the achievement level.

Code Explanation:

• First, we declare a variable 'score' and assign it the value 85 using let score = 85;
• The first if statement checks if the score is greater than 90 (score > 90). If true, it prints "Excellent!" indicating outstanding performance.
• If the first condition is false, the else if statement checks if the score is greater than 75 (score > 75). In this case, since 85 is greater than 75, it prints "Good job!" acknowledging satisfactory performance.
• The else statement handles all scores 75 and below, printing "Keep trying!" to encourage improvement.

Program Flow:

• In this example, since score = 85:
• First check: Is 85 > 90? No, move to next condition
• Second check: Is 85 > 75? Yes, execute console.log("Good job!")
• Program ends after executing the matching condition

Common Use Cases:

• Grade evaluation systems
• Performance assessment
• Decision-making based on numerical thresholds
• User feedback systems

Simulate It!