EFREI-2026-L3-HUNGARY-Java-1

README.md

EFREI 2026 L3 HUNGARY Java 1 (24/09/23)

Deadline

• 24/09/2023

Guidelines

• Exercice 1

  • Create a zoo (of some sorts)
  • Have a common ancestor class: animal
  • Each animal should have a name
  • Have a three other classes that extend that class (zebra, elephant, python)
  • Implement the makesound feature that we have seen on the slide.
  • The animals should have their own methods and variables (use your imagination)
  • Create an interface called hasLegs with a letsRun method and a getNumberOfLegs method and then implement that interface for the animals that have legs.
  • Create a common array for the animals (did not understood this assignement => skipped)

• Exercice 2

  • Write a program that takes a number from standard input and displays it. For this, we will use an object (an instance) of the Scanner class and particularly its nextInt() method.

• Exercice 3

  • Modify the previous program (did not understood this assignement => made a new class) so that it reads from the keyboard a series of positive or zero real numbers (corresponding to notes), ending in the value -1, and calculates the Olympic average of these values, i.e. the average of the scores regardless of the highest or lowest score.

Animal.java

package zoo;

public abstract class Animal {
	protected String name;

	public Animal(String name) {
		this.name = name;
	}

	public abstract void makeSound();

	public String getName() {
		return name;
	}
}

Elephant.java

package zoo;

public class Elephant extends Animal implements HasLegs {
	private int numberOfLegs;
	private boolean hasTrunk;

	public Elephant(String name, int numberOfLegs, boolean hasTrunk) {
		super(name);
		this.numberOfLegs = numberOfLegs;
		this.hasTrunk = hasTrunk;
	}

	public void makeSound() {
		System.out.println("Elephant is making a sound");
	}

	public void letsRun() {
		System.out.println("Elephant is running.");
	}

	public int getNumberOfLegs() {
		return numberOfLegs;
	}

	public boolean hasTrunk() {
		return hasTrunk;
	}

	public void sprayWater() {
		System.out.println("Elephant is spraying water.");
	}
}

HasLegs.java

package zoo;

public interface HasLegs {
	void letsRun();
	int getNumberOfLegs();
}

NumberDisplayProgram.java

package input;

import java.util.Scanner;

public class NumberDisplayProgram {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		System.out.print("Enter a number: ");

		if (scanner.hasNextInt()) {
			int number = scanner.nextInt();
			System.out.println("You entered: " + number);
		} else {
			System.out.println("Invalid input. Please enter a valid integer.");
		}

		scanner.close();
	}
}

OlympicAverageCalculator.java

package input;

import java.util.InputMismatchException;
import java.util.Scanner;

public class OlympicAverageCalculator {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		double sum = 0;
		int count = 0;

		System.out.println("Enter positive or zero real numbers, end with -1:");

		while (true) {
			try {
				double input = scanner.nextDouble();

				if (input == -1)
					break;

				if (input >= 0) {
					sum += input;
					count++;
				} else {
					System.out.println("Please enter a non-negative number.");
				}
			} catch (InputMismatchException e) {
				System.out.println("Invalid input. Please enter a valid real number.");
				scanner.next(); // Clear the invalid input from the scanner
			}
		}

		double average = count > 0 ? sum / count : 0;
		System.out.println("Olympic average: " + average);

		scanner.close();
	}
}

Python.java

package zoo;

public class Python extends Animal {
	private boolean isVenomous;
	private int lengthInFeet;

	public Python(String name, boolean isVenomous, int lengthInFeet) {
		super(name);
		this.isVenomous = isVenomous;
		this.lengthInFeet = lengthInFeet;
	}

	public void makeSound() {
		System.out.println("Python is making a sound");
	}

	public boolean isVenomous() {
		return isVenomous;
	}

	public int getLengthInFeet() {
		return lengthInFeet;
	}

	public void slither() {
		System.out.println("Python is slithering.");
	}
}

Zebra.java

package zoo;

public class Zebra extends Animal implements HasLegs {
	private int numberOfLegs;
	private boolean isStriped;

	public Zebra(String name, int numberOfLegs, boolean isStriped) {
		super(name);
		this.numberOfLegs = numberOfLegs;
		this.isStriped = isStriped;
	}

	public void makeSound() {
		System.out.println("Zebra is making a sound");
	}

	public void letsRun() {
		System.out.println("Zebra is running.");
	}

	public int getNumberOfLegs() {
		return numberOfLegs;
	}

	public boolean isStriped() {
		return isStriped;
	}

	public void eatGrass() {
		System.out.println("Zebra is eating grass.");
	}
}