Java Type Casting

Java Type Casting

Type casting in Java occurs when you assign a value from one primitive data type to another.

In Java, casting can be categorized into two types:

Widening Casting(automatically) – Expanding the size of a type.

byte -> short -> char -> int -> long -> float -> double

Narrowing Casting (manually) – Reducing the size of a type.

double -> float -> long -> int -> char -> short -> byte

Widening Casting

Automatic widening casting occurs when passing a smaller-sized type to a larger-sized type.

Example

public class Main { 
public static void main(String[] args) {
    int myInt = 9;
    double myDouble = myInt; // Automatic casting: int to double

    System.out.println(myInt);      // Outputs 9
    System.out.println(myDouble);   // Outputs 9.0
  }
}

Narrowing Casting

Manual narrowing casting is performed by enclosing the type in parentheses ( ) before the value.

Example

public class Main {
 public static void main(String[] args) {
    double myDouble = 9.78d;
    int myInt = (int) myDouble; // Manual casting: double to int

    System.out.println(myDouble);   // Outputs 9.78
    System.out.println(myInt);      // Outputs 9
  }
}

Real-Life Example

Below is an example demonstrating type casting in action, where we develop a program to determine the percentage of a user’s score relative to the maximum score achievable in a game.

We utilize type casting to ensure that the outcome is a floating-point value, as opposed to an integer.

Example