? Java Type Casting

Type casting in Java is the process of converting one data type into another. There are two types:

? 1. Widening Casting (Implicit Casting)

• Also known as automatic type conversion.

• Happens when converting a smaller type to a larger type size.

• byte ? short ? int ? long ? float ? double

Example:

int num = 100;double d = num;  // int is automatically cast to doubleSystem.out.println(d);  // Output: 100.0

? 2. Narrowing Casting (Explicit Casting)

• Must be done manually by the programmer.

• Converts a larger type into a smaller size type.

• Can lead to data loss.

Syntax:

dataType variableName = (dataType) value;

Example:

double d = 9.78;int i = (int) d;  // Explicit casting: double to intSystem.out.println(i);  // Output: 9 (decimal part is lost)

? Special Cases

a. Casting between char and int

char ch = 'A';int ascii = (int) ch;  // Output: 65int num = 66;char letter = (char) num;  // Output: 'B'

b. Casting Objects (Reference Type Casting)

There are two types:

• Upcasting: Subclass ? Superclass (Implicit)

• Downcasting: Superclass ? Subclass (Explicit)

Example:

class Animal {    void sound() {        System.out.println("Animal sound");    }}class Dog extends Animal {    void sound() {        System.out.println("Dog barks");    }    void fetch() {        System.out.println("Dog fetches");    }}Animal a = new Dog();  // Upcastinga.sound();             // Output: Dog barksDog d = (Dog) a;       // Downcastingd.fetch();             // Output: Dog fetches

? Summary Table

Let me know if you want a cheat sheet or exercises on this topic!