Java Programming Introduction

Java Programming Introduction

• Java is a programming language used to create applications.
• The Scanner class is used for accepting input from the user.
• The import java.util.Scanner; line imports the necessary class.
• A Scanner object is created using Scanner input = new Scanner(System.in);
• System.in refers to the keyboard input.

Scanner Methods

• nextInt(): Reads an integer from the user.
• nextDouble(): Reads a double-precision floating-point number from the user.
• nextFloat(): Reads a single-precision floating-point number from the user.
• next(): Reads a string from the user, up to the next whitespace.
• next().charAt(0): Reads a character from the user input.
• Each method waits for the user to press Enter.

Example Usage (Scanner)

• Get user input for age:

System.out.print("How old are you? ");
int age = input.nextInt();
System.out.println("You typed " + age);

Java Math Class

• Provides mathematical functions.
• Math.abs(value): Returns the absolute value of a number.
• Math.ceil(value): Rounds a number up to the nearest integer.
• Math.floor(value): Rounds a number down to the nearest integer.
• Math.log10(value): Returns the base-10 logarithm of a number.
• Math.max(value1, value2): Returns the larger of two values.
• Math.min(value1, value2): Returns the smaller of two values.
• Math.pow(base, exp): Returns base raised to the power of exp.
• Math.random(): Returns a random double between 0.0 (inclusive) and 1.0 (exclusive).
• Math.round(value): Rounds a number to the nearest integer.
• Math.sqrt(value): Returns the square root of a number.
• Math.sin(value), Math.cos(value), Math.tan(value): Trigonometric functions (value in radians).
• Math.toDegrees(value), Math.toRadians(value): Converts between degrees and radians.
  • Math.E: Euler's number (approximately 2.71828).
  • Math.PI: Pi (approximately 3.14159).
• Math methods do not print directly to the console.
• The result is a numerical value

Type Casting

• Converts a variable from one data type to another.
• (type) expression: Explicit type casting.
• Example: (double) 19 / 5 converts the result of the division to a double-precision number.
• (int) Math.pow(10, 3) truncates Math.pow's results to an integer.

Calling Math Methods

• Parameters provide input; return values give outputs from the method.

Example: Hypotenuse Calculation

• Calculate the hypotenuse of a right-angled triangle using user input for the sides

import java.util.Scanner; // Import necessary class
public class Main {
    public static void main(String[] args) {
	Scanner input = new Scanner(System.in); //Create an object from Scanner class
		//Get the inputs from user
		System.out.print("Please Enter the value of side 1");
		double side1 = input.nextDouble();
		System.out.print("Please Enter the value of side 2");
		double side2 = input.nextDouble();
		//Calculate hypotenuse
		double hypotenuse = Math.sqrt((side1 * side1) + (side2 * side2));
		//Display output to user
	System.out.println("The length of the hypotenuse is :"+hypotenuse);
	}
}

This quiz covers the basics of Java programming, focusing on the Scanner class for user input and various methods to read different data types. It includes examples and explanations to help you understand how to effectively use the Java Math class and input methods. Perfect for beginners looking to solidify their foundational knowledge in Java.