Day 3: Mastering Operators and Expressions in JavaScript

Introduction

Welcome to Day 3 of your JavaScript journey! Yesterday, we explored variables and data types. Today, we will dive into operators and expressions, which are fundamental for performing calculations and making decisions in your code.

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Arithmetic Operators

Arithmetic operators allow you to perform mathematical operations on numbers.

1. Addition (+)
Adds two numbers.

let sum = 5 + 3;
console.log(sum); // Output: 8

2. Subtraction (-)
Subtracts the second number from the first.

let difference = 9 - 4;
console.log(difference); // Output: 5

3. Multiplication (*)
Multiplies two numbers.

let product = 7 * 2;
console.log(product); // Output: 14

4. Division (/)
Divides the first number by the second.

let quotient = 10 / 2;
console.log(quotient); // Output: 5

5. Modulus (%)
Returns the remainder of the division.

let remainder = 10 % 3;
console.log(remainder); // Output: 1

6. Increment (++)
Increases a number by one.

let count = 5;
count++;
console.log(count); // Output: 6

7. Decrement (--)
Decreases a number by one.

let count = 5;
count--;
console.log(count); // Output: 4

Comparison Operators

Comparison operators compare two values and return a boolean (true or false).

1. Equal (==)
Checks if two values are equal (type conversion may occur).

let isEqual = (5 == '5');
console.log(isEqual); // Output: true

2. Strict Equal (===)
Checks if two values are equal and of the same type.

let isStrictEqual = (5 === '5');
console.log(isStrictEqual); // Output: false

3. Not Equal (!=)
Checks if two values are not equal (type conversion may occur).

let isNotEqual = (5 != '5');
console.log(isNotEqual); // Output: false

4. Strict Not Equal (!==)
Checks if two values are not equal or not of the same type.

let isStrictNotEqual = (5 !== '5');
console.log(isStrictNotEqual); // Output: true

5. Greater Than (>)
Checks if the left value is greater than the right value.

let isGreaterThan = (6 > 3);
console.log(isGreaterThan); // Output: true

6. Less Than (<)
Checks if the left value is less than the right value.

let isLessThan = (6 < 3);
console.log(isLessThan); // Output: false

7. Greater Than or Equal (>=)
Checks if the left value is greater than or equal to the right value.

let isGreaterThanOrEqual = (6 >= 6);
console.log(isGreaterThanOrEqual); // Output: true

8. Less Than or Equal (<=)
Checks if the left value is less than or equal to the right value.

let isLessThanOrEqual = (6 <= 6);
console.log(isLessThanOrEqual); // Output: true

Logical Operators

Logical operators are used to combine multiple conditions.

1. Logical AND (&&)
Returns true if both operands are true.

let andResult = (5 > 3 && 8 > 6);
console.log(andResult); // Output: true

2. Logical OR (||)
Returns true if at least one operand is true.

let orResult = (5 > 3 || 8 < 6);
console.log(orResult); // Output: true

3. Logical NOT (!)
Inverts the truthiness of the operand.

let notResult = !(5 > 3);
console.log(notResult); // Output: false

Expressions

Expressions are combinations of variables, operators, and values that yield a result.

Example:

let a = 10;
let b = 5;
let c = a + b * 2;
console.log(c); // Output: 20

Practice Activities

1. Practice Code:

• Write expressions using each arithmetic, comparison, and logical operator.
• Combine multiple operators in complex expressions.

2. Mini Project:

• Create a simple calculator script that performs basic arithmetic operations based on user input.

Example:

let num1 = parseFloat(prompt("Enter the first number:"));
let num2 = parseFloat(prompt("Enter the second number:"));
let operation = prompt("Enter the operation (+, -, *, /, %):");

let result;
if (operation === "+") {
  result = num1 + num2;
} else if (operation === "-") {
  result = num1 - num2;
} else if (operation === "*") {
  result = num1 * num2;
} else if (operation === "/") {
  result = num1 / num2;
} else if (operation === "%") {
  result = num1 % num2;
} else {
  result = "Invalid operation";
}

console.log("Result:", result);

Summary

Today, we explored operators and expressions in JavaScript. We learned how to use arithmetic, comparison, and logical operators to build expressions and perform calculations. Understanding these operators is crucial for making decisions and manipulating data in your code.

Series Index

Part	Title	Link
1	Day 1: Getting Started with JavaScript	Read Part 1
2	Day 2: Understanding Variables and Data Types in JavaScript	Read Part 2
3	Day 3: Mastering Operators and Expressions in JavaScript	Read Part 3
4	Day 4: Control Structures in JavaScript	Read Part 4
5	Day 5: Understanding Functions in JavaScript	Read Part 5
6	Day 6: Mastering Arrays in JavaScript 🚀	Read Part 6
7	Day 7: Understanding Objects in JavaScript 🏆	Read Part 7

Stay tuned for Day 4, where we'll dive into control structures like conditionals and loops!

Resources

• Expressions and Operators
• JavaScript Basics

Happy coding! If you have any questions or need further clarification, feel free to leave a comment below. Let's continue learning and growing together!

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