Implicit conversions

Implicit conversions

Implicit conversions are performed whenever an expression of some type T1 is used in context that does not accept that type, but accepts some other type T2; in particular:

  • when the expression is used as the argument when calling a function that is declared with T2 as parameter;
  • when the expression is used as an operand with an operator that expects T2;
  • when initializing a new object of type T2, including return statement in a function returning T2;
  • when the expression is used in a switch statement (T2 is integral type);
  • when the expression is used in an if statement or a loop (T2 is bool).

The program is well-formed (compiles) only if there exists one unambiguous implicit c