What is the difference between int and (int) in C?

Question

For example: when I round a float into an int, why should I use :

int i = (int) round(f);

Instead of :

int i = int round(f);

Answer 1

What is the difference between int and (int) in C?

an int is the built-in type integer and (int) is Type Casting .

Answer 2

In C float data values require more storage, So when you are storing a float value in an integer variable you are supposed to type cat it to truncate the fractional part before storing it.

ie int i = (int) round(f);

Answer 3

Did you actually try to compile the latter? I will not answer that until you report what the compiler says.

For the first version: That is a typecast (read about the semantics), telling the compiler to convert the value to the type in the parenthesis. Otherwise the compiler might (should) complain about assigning a more "powerful" type to a lesser.

Note that "powerful" here means the type can hold a larger range of values; not necessarily higher precision.

Edit: Yes, you will get "expected expression" for the latter. Because that is simply invalid. So, the simple and full answer is: because the second thing is not valid C and will not even compiler!

Answer 4

use int i is a definition.

(int) round(f) is casting the results of the round function to an integer, potentially truncating results of round down to an integer

Answer 5

Well by convention, doing (int) on a float is typecasting the float to an int. I'm not quite sure why you'd do int _ = int _ , although it may work just as well. By convention though, many languages (there are exceptions) in which you typecast go by the syntax of

... = (_type_) yourdatavalue

Hope that helps!