Implicit type conversion, also known as "coercion", is an automatic type conversion by the compiler. Implicit conversions do not require any operator. They are automatically performed when a value is copied to a compatible type. In a mixed type expression, a subtype s will be converted to a supertype t or some subtypes s₁, s₂, ... will be converted to a supertype t (maybe none of the s_i is of type t) at runtime so that the program will run correctly. For example:

double d;
long l;
int i;
if (d > i) d = i;
if (i > l) l = i;
if (d == l) d *= 2;


Although d, l and i belong to different datatypes, they will be automatically converted to the same datatype each time a comparison or assignment is executed.

See also:

explicit type conversion

Converting Overview (MSDN); Type Conversion Tables (MSDN); Explicit conversion (MSDN); Usual Arithmetic Conversions (MSDN)