Course Content

Java Extended

1. Deep Java Structure

How Does the Compiler Works?Data Transfer in Java Final Keyword Importing Libraries Using Libraries In Our Code Ternary Operator Enhanced Switch Statement

2. Methods

What is a Method?Creating Our Own Methods Challenge: Names Starting with Letter B Void Methods Practice Method Overloading Recursion Challenge: Find Maximum and Minimum in Array

3. String Advanced

Deeper into String Method split()Challenge: Uppercase Even Words indexOf() Method Challenge: Finding the Longest Word trim() Method Challenge: Email Validation

4. Classes

What is Class?Main Class and Method Access Modifiers Class Creation Challenge: Get Information About the Object Constructor Challenge: Team Constructor Method toString()Challenge: Parrot Information Display

5. Classes Advanced

Complex Classes Usage Challenge: Pet and Owner Relationship Private Modifier Challenge: Animal Information Display Getter and Setter Challenge: Updating User Information Summary

Class Creation

Class Syntax

The syntax for creating a class is quite simple. Let's take a look at an example with the class Person:

Person


              123
            
class Person {

}

This is all it takes to create a class. However, it will be useless to us if it's empty. Therefore, we should add fields to it. Let's assume that our person has a name, gender, and age:

Person


              12345
            
class Person {
    String name;
    String gender;
    int age;
}

And now, let's write a method that allows our Person to report their name and age:

Person


              123456789
            
class Person {
    String name;
    String gender;
    int age;
    
    void introduce() {
        System.out.println("Hi, my name is " + name + " and I am " + age + " years old!");
    }
}

Task

Swipe to show code editor

Alice wants to find a friend within a specific age range (25 - 30, inclusive). You need to write a program that checks whether Bob meets Alice's criteria. If Bob's age falls within the specified range, the program should return true; otherwise, it should return false.

In the main method, you need to pass the correct object as the first parameter to the findFriend method.
In the findFriend method, compare the age of the passed object with the specified age range (25 - 30).
If the object falls within the age range, return true; otherwise, return false.
To display the result on the screen, use the foundFriend variable, which stores the result of the search.

Solution

solution

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Section 4. Chapter 4

Class Creation

Class Syntax

The syntax for creating a class is quite simple. Let's take a look at an example with the class Person:

Person


              123
            
class Person {

}

This is all it takes to create a class. However, it will be useless to us if it's empty. Therefore, we should add fields to it. Let's assume that our person has a name, gender, and age:

Person


              12345
            
class Person {
    String name;
    String gender;
    int age;
}

And now, let's write a method that allows our Person to report their name and age:

Person


              123456789
            
class Person {
    String name;
    String gender;
    int age;
    
    void introduce() {
        System.out.println("Hi, my name is " + name + " and I am " + age + " years old!");
    }
}

Task

Swipe to show code editor

In the main method, you need to pass the correct object as the first parameter to the findFriend method.
In the findFriend method, compare the age of the passed object with the specified age range (25 - 30).
If the object falls within the age range, return true; otherwise, return false.
To display the result on the screen, use the foundFriend variable, which stores the result of the search.

Solution

solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 4

Switch to desktop for real-world practiceContinue from where you are using one of the options below