Course Content

Java Basics

1. Getting Started

Backend Development Role of Java in the Backend Java Advantages Memory Types In Java Java's Syntax Your First Program Comments

2. Basic Types and Operations

Primitive Data Types Challenge: Primitive Types Mathematical Operations on char Mathematical Operations in Java If-Else Statement Switch-Case Statement Challenge: Weekday Switch

3. Loops

Introduction to Loops While-Loop Do-While Loop Challenge: Building a Server Retry Mechanism For-Loop Increment and Decrement Infinite Loop Challenge: Filtering Numbers in a Loop

4. Arrays

What is Array?Using Loops with Arrays Index Out Of Bounds Two-Dimentional Array Iteration In Two-Dimensional Array For-Each Loop

5. String

What Is String? Basic Methods In String Practical Applications of String Methods Challenge: Filter Failure Messages NullPointerException StringBuilder String Pool, Method Equals() Summary

Mathematical Operations in Java

Operators

We observed that we used basic mathematical operators such as +, -, /, and *. These operators are familiar to us from calculators or mathematics; you can also use them in a code editor.

Let's go through the basics:

+ – addition;
- – subtraction;
/ – division;
* – multiplication.

You can use these four fundamental operators with numerical data types (byte, short, long, float, double).

Let's explore the usage of these operators with an example code:

Main


              1234567891011121314
            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Creating an int variable with value 10
        int a = 10; 
        // Creating an int variable with value 17
        int b = 17; 
        // Creating an int variable to store the sum of `a` and `b`
        int res = a + b; 
        // Printing the result to the console
        System.out.println(res); 
   }
}

As we can see, the variable res holds the value 27, which is the sum of 10 and 17.

Let's consider a few more examples:

Main


              12345678910111213141516171819
            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Creating an int variable with the sum of 16 and 4
        int plus = 16 + 4; 
        /* Creating an int variable with the value of the subtraction 
        of the `plus` variable and 10 */ 
        int minus = plus - 10; 
        /* Variable that holds the result of multiplying 
        the `minus` variable by 4 */ 
        int multiplying = minus * 4; 
        /* Using subtraction and division operations 
        on the `multiplying` variable */ 
        int complexDivision = (multiplying - 4) / 9; 
        // Printing the result to the console
        System.out.println(complexDivision); 
    }
}

We can use both numbers and variables in our operations. However, it's worth remembering that creating multiple variables adds to the stack memory. Therefore, it's recommended to use regular numbers when possible. Additionally, we can observe that operator precedence is followed. Operations inside parentheses are performed first, followed by multiplication or division, and then addition or subtraction.

In this way, we can perform simple operations with different numeric data.

Order of operations

Java follows the basic principles of mathematics, and operations also have an order of execution. Let's take a look at an example:

main


              12345678
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int result = (10 + 5) * 2 - 8 / 4 + 1;
        System.out.println(result);
    }
}

Here we arrived at the result by performing operations sequentially. Let's take a look at the order:

So, you can prioritize the execution of operations using regular parentheses, just like in arithmetic.

Task

Swipe to start coding

Add the values of the variables firstNumber and secondNumber.
Divide the sum by the value of the variable thirdNumber.
Store the final result in the variable result.

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 2. Chapter 4

Mathematical Operations in Java

Operators

We observed that we used basic mathematical operators such as +, -, /, and *. These operators are familiar to us from calculators or mathematics; you can also use them in a code editor.

Let's go through the basics:

+ – addition;
- – subtraction;
/ – division;
* – multiplication.

You can use these four fundamental operators with numerical data types (byte, short, long, float, double).

Let's explore the usage of these operators with an example code:

Main


              1234567891011121314
            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Creating an int variable with value 10
        int a = 10; 
        // Creating an int variable with value 17
        int b = 17; 
        // Creating an int variable to store the sum of `a` and `b`
        int res = a + b; 
        // Printing the result to the console
        System.out.println(res); 
   }
}

As we can see, the variable res holds the value 27, which is the sum of 10 and 17.

Let's consider a few more examples:

Main


              12345678910111213141516171819
            
package com.example;

public class Main {
    public static void main(String[] args) {
        // Creating an int variable with the sum of 16 and 4
        int plus = 16 + 4; 
        /* Creating an int variable with the value of the subtraction 
        of the `plus` variable and 10 */ 
        int minus = plus - 10; 
        /* Variable that holds the result of multiplying 
        the `minus` variable by 4 */ 
        int multiplying = minus * 4; 
        /* Using subtraction and division operations 
        on the `multiplying` variable */ 
        int complexDivision = (multiplying - 4) / 9; 
        // Printing the result to the console
        System.out.println(complexDivision); 
    }
}

In this way, we can perform simple operations with different numeric data.

Order of operations

Java follows the basic principles of mathematics, and operations also have an order of execution. Let's take a look at an example:

main


              12345678
            
package com.example;

public class Main {
    public static void main(String[] args) {
        int result = (10 + 5) * 2 - 8 / 4 + 1;
        System.out.println(result);
    }
}

Here we arrived at the result by performing operations sequentially. Let's take a look at the order:

So, you can prioritize the execution of operations using regular parentheses, just like in arithmetic.

Task

Swipe to start coding

Add the values of the variables firstNumber and secondNumber.
Divide the sum by the value of the variable thirdNumber.
Store the final result in the variable result.

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 2. Chapter 4

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