From NSData to NSString:

NSString *s = [[NSString alloc] initWithData:d encoding:NSUTF8StringEncoding];

And the other way round:

NSData *d = [s dataUsingEncoding:NSUTF8StringEncoding]:

printf ("floats: %4.2f %+.0e %E \n", 3.1416, 3.1416, 3.1416); floats: 3.14 +3e+000 3.141600E+000

CGPoint CGPointMake ( CGFloat x, CGFloat y );

x, y has to be floats, passing only integers might not work.

especially good to know, when and if ints get converted into floats.

= CGPointMake(100.0f + someIntVar, 50.0f + anotherIntVar); ≠ CGPointMake(100 + someIntVar, 50 + anotherIntVar);

this .0f seems to have a meaning after all.