A conversion enables an expression of one type to be treated as another type. Conversions can be implicit or explicit, and this determines whether an explicit cast is required. [Example: For instance, the conversion from type int to type long is implicit, so expressions of type int can implicitly be treated as type long . The opposite conversion, from type long to type int , is explicit and so an explicit cast is required.

int a = 123; long b = a; // implicit conversion from int to long int c = (int) b; // explicit conversion from long to int

end example] Some conversions are defined by the language. Programs may also define their own conversions (13.4).

In This Section:

• 13.1: Implicit conversions
• 13.2: Explicit conversions
• 13.3: Standard conversions
• 13.4: User-defined conversions