Time to explore 2 - Data Type Examples 😎

📊 Examples with Numbers and Strings

In this lesson, we’ll learn about different data types in Java — these are the kinds of values your robot can use, like numbers, letters, and words. Each type has its own special rules and powers. Let’s check them out!


🔢 Integers (int)

Integers are whole numbers. That means they don’t have decimals. You can use them to count things, measure scores, or store positions.

int score = 10;
int lives = 3;

Java automatically uses integer math when you’re working with just int numbers.

OperationCodeWhat It DoesResult
Additionint sum = 5 + 2;5 plus 27
Subtractionint diff = 5 - 2;5 minus 23
Multiplicationint product = 5 * 2;5 times 210
Divisionint quotient = 5 / 2;5 divided by 2, decimal gets cut off2
Remainderint rem = 5 % 2;What’s left after dividing 5 by 21

📝 Note: If you divide 5 / 2 using int, you don’t get 2.5 — Java chops off the decimal and gives just 2.


🧮 Decimal Numbers (double)

A double can store decimal numbers like 2.5 or 3.14. It’s great for when you need precise values, like distances or percentages.

double speed = 2.5;
double batteryLevel = 75.5;
OperationCodeWhat It DoesResult
Multiplicationdouble r = 4.5 * 1.2;4.5 times 1.25.4
Order of Opsdouble r = 4.5 * 1.2 + 3;Multiply first, then add8.4
Divisiondouble d = 5.0 / 2.0;Divides with decimals2.5

Reminder: To get a decimal answer, at least one number must have a .0 in it! If both numbers are int, you’ll get an int result.


🔤 Characters (char)

A char (short for character) stores a single letter or symbol. It’s surrounded by single quotes like 'A' or '%'.

char grade = 'A';
char symbol = '!';
OperationCodeWhat It DoesResult
Assign letterchar letter = 'A';Stores letter A'A'
Next letterchar next = (char)(letter + 1);Adds 1 to A (ASCII code) = B'B'
Symbolchar symbol = '!';Stores exclamation mark'!'

💡 Fun Fact: Letters are secretly stored as numbers (ASCII). 'A' is 65, 'B' is 66, and so on!


🧵 Strings

A String is a bunch of characters stuck together — like a word or sentence. You use double quotes for strings: "Hello"

String name = "Robo";
String message = "Hello, world!";
OperationCodeWhat It DoesResult
Basic join"Hello" + " World"Joins the two parts together”Hello World”
Add variable"Hello, " + nameAdds the value inside name”Hello, Robo”
Add number to string"Score: " + 10Turns 10 into text, then joins it”Score: 10”
Multi-line"Line1\nLine2"\n makes a new lineLine1 (newline) Line2

💡 Tip: Strings aren’t just text — they’re objects that have cool powers like .length() (how long it is) and .toUpperCase() (shouty version!)


🧠 Summary Table

Data TypeWhat It’s ForExamplesNotes
intWhole numbers5 + 2, 10 / 3, 7 % 4No decimals, does regular math
doubleDecimal numbers5.0 / 2.0, 3.14 * 2, 1.5 + 3Gives accurate decimal answers
charSingle characters'A', 'Z', '!', '1'Must use single quotes ' ', ASCII aware
StringWords and sentences"Hello" + name, "Score: " + 5Double quotes, use + to build messages

🧪 Challenge: Try printing out these different types using System.out.println() and see what happens!

System.out.println(5 + 2);           // int math
System.out.println(5.0 / 2.0);       // double math
System.out.println('A' + 1);         // adds to char, prints number!
System.out.println("Hi " + "there!"); // String join

➡️ 🤖 Minigame!

⬅️ Back: Variables ➡️ Output