Class-4

Class 4 – Introduction to JavaScript

Class Slides: class 4.1

This lecture focuses on data conversion, comparison and logical operators, conditional statements, and loops in JavaScript, which are essential for writing interactive and logical programs.

Key Topics Covered:

1. Converting Strings to Numbers:

• parseInt(): Converts a string to an integer and stops reading at the first non-numeric character.
• parseFloat(): Converts a string to a floating-point number and preserves decimal values.
• Number(): Converts an entire string to a number, including both integers and floats.
• toFixed(): Rounds a number to a specified number of decimal places.

2. Comparison Operators:

• Used to compare values and return true or false.
• == (Equality): Compares values without checking data type.
• === (Strict Equality): Compares both value and data type.
• != (Not Equal) and !== (Strict Not Equal).
• <, >, <=, >= for numerical comparisons.

3. Logical Operators:

• && (AND): Returns true if both conditions are true.
• || (OR): Returns true if at least one condition is true.
• ! (NOT): Inverts the boolean value.
• Short-Circuiting: && stops evaluating when it finds false, and || stops when it finds true.

4. Conditional Statements:

• if statement: Executes a block of code if a condition is true.
• if-else: Adds an alternative execution when the condition is false.
• else if: Specifies multiple conditions.

5. Loops in JavaScript:

• For Loop: Runs a block of code a fixed number of times.
• While Loop: Runs as long as a condition remains true.
• Break & Continue:
  • break: Exits the loop immediately.
  • continue: Skips the current iteration and proceeds to the next.
• Nested Loops: A loop inside another loop to handle multiple iterations.

This lecture provides fundamental concepts of data type conversion, logical decision-making, and looping, which are crucial for writing efficient JavaScript programs. Understanding these topics enhances code functionality, automation, and user interaction.