In the last lesson, we learned to create variables.
For example:
int age;
● In Java, "int" is a primitive data type that is used to represent whole numbers. It is a 32-bit signed two's complement integer, which means it can represent values between -2,147,483,648 and 2,147,483,647.
● Integers are a fundamental data type in Java, and they are used in a wide variety of applications.
Data types determine the type and the size of variables. The int variables
● can only store integers (type)
● are typically 4 bytes (size)
In Java, we cannot create variables without a data type.
● The int variables can only store integers.
● The size of an int variable is usually 4 bytes (32 bits).
● This means it can take 2^32 distinct integer values from -2147483648 to 2147473647.
Example:
Int age, userId = 45;
Here, age and userId are int type variables. And, we have assigned 45 to the userId variable.
● Both float and double variables can only store floating-point numbers (decimal numbers).
● The size of a double variable is 8 bytes. And, the size of a float variable is 4 bytes.
● This means double variables can store real numbers with better precision.
Example:
Double firstNumber = 64.33;
Float secondNumber = 64.33f;
Here, both variables are storing 64.33 , However for float types we use f or F at the end.
● Both float and double variables can only store floating-point numbers (decimal numbers).
● The size of a double variable is 8 bytes. And, the size of a float variable is 4 bytes.
● This means double variables can store real numbers with better precision.
Example:
double firstNumber = 64.33;
float secondNumber = 64.33f;
Here, both variables are storing 64.33 , However for float types we use f or F at the end.
The boolean variables can only store two values: true or false.
Example:
Boolean result1 = true;
Boolean result2 = false;
Booleans are used in decision making and loops which we will learn in upcoming lessons.