“f” after number

Question

What does the f after the numbers indicate? Is this from C or Objective-C? Is there any difference in not adding this to a constant number?

CGRec         


        

Answer 1

When in doubt check the assembler output. For instance write a small, minimal snippet ie like this

#import 

void test() {
  CGRect r = CGRectMake(0.0f, 0.0f, 320.0f, 50.0f);
  NSLog(@"%f", r.size.width);
}

Then compile it to assembler with the -S option.

gcc -S test.m

Save the assembler output in the test.s file and remove .0f from the constants and repeat the compile command. Then do a diff of the new test.s and previous one. Think that should show if there are any real differences. I think too many have a vision of what they think the compiler does, but at the end of the day one should know how to verify any theories.