the 'f' suffix is just a printf Conversion-type character.
Any number that's suffixed with an 'f' just shows that its expected type is a floating point.
Here are the other Conversion-type characters.
QUOTE
Type Char Expected Input Format of output
d Integer signed decimal integer
i Integer signed decimal integer
o Integer unsigned octal integer
u Integer unsigned decimal integer
x Integer unsigned hexadecimal int (with a, b, c, d, e, f)
X Integer unsigned hexadecimal int (with A, B, C, D, E, F)
f Floating point signed value of the form [-]dddd.dddd.
e Floating point signed value of the form [-]d.dddd or e
[+/-]ddd
g Floating point signed value in either e or f form, based on given value and precision. Trailing zeros and the decimal point are printed if necessary.
E Floating point Same as e; with E for exponent.
G Floating point Same as g; with E for exponent if e format used
Characters
c Character Single character
s String pointer Prints characters until a null-terminator is pressed or precision is reached
% None Prints the % character
Pointers
n Pointer to int Stores (in the location pointed to by the input argument) a count of the chars written so far.
p Pointer Prints the input argument as a pointer; format depends on which memory model was used. It will be either XXXX:YYYY or YYYY (offset only).
Source : Borland Help