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.