Typecasting in C

[thiruvasagamani]

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:


 

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int integernumber;
  float floatnumber=9.87;
  integernumber=(int)floatnumber;


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


And:

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int integernumber=10;
  float floatnumber;
  floatnumber=(float)integernumber;


assigns 10.0 to floatnumber.

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


               

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  int integernumber;
char letter='A';
                 integernumber=(int)letter;

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 :


e.g.

floatnumber =
       (float) internumber / (float) anotherint;


ensures floating point division.