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Coercion or Type-Casting

C is one of the few languages to allow coercion, that is forcing one variable of one type to be another type. C allows this using the cast operator (). So:

assigns 9 (the fractional part is thrown away) to integernumber.


assigns 10.0 to floatnumber.

Coercion can be used with any of the simple data types including char, so:

assigns 65 (the ASCII code for `A') to integernumber.

Some typecasting is done automatically - this is mainly with integer compatibility.

A good rule to follow is: If in doubt cast.

Another use is the make sure division behaves as requested: If we have two integers internumber and anotherint and we want the answer to be a float then :

ensures floating point division.
Fri May 20 13:40:49 BST 1994