Summary - Variables

Combine int, double and String to write a profile card.

Summary - Variables

In this group you learned Java's basic variable types:

int: for integers
double: for decimals
boolean: for true/false
String: for text
final: for constants

Variable names use camelCase, constants use ALL_CAPS. Now combine them and write a profile card.

Exercise Write a profile card

Write a Main class with a main method. Assign "Alex" to String name and 28 to int age. Print both with println.

Show example solution

public class Main {
    public static void main(String[] args) {
        String name = "Alex";
        int age = 28;
        System.out.println(name);
        System.out.println(age);
    }
}

Next steps

You now know the basic variable types. In the next groups you will see:

Type casting and the Math class
String methods (length, substring)
Conditionals (if, switch)
Loops (for, while)
Arrays and collections

To keep the knowledge fresh, write your own small programs. Declare variables, assign values, and print with println. With practice the concepts will settle in.

Exercise Final constant with a profile

Write a Main class with a main method. Assign "London" to final String CITY. Print it with println.

Show example solution

public class Main {
    public static void main(String[] args) {
        final String CITY = "London";
        System.out.println(CITY);
    }
}

Test yourself

Match the types

int

Integer
double

Decimal
boolean

Logical
String

Text

Define a constant

final int MAX_USERS = ____;

Show answer

final int MAX_USERS = 100;

Next lesson: Primitive types

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