just a question on the Get That Discount! puzzle in c#

Question

so in the solution i see:
if (i <= 10000)
i = (int)(i*0.8f)
return i;
what does the "f" after the 0.8 do?
and also my code was:
if (i <= 10000) {
i = (int)(i - 0.2*i)
return i;
(like the explanation part says: (i - 0.2*i))

Answer 1

The "f" after the 0.8 tells the compiler that you're entering a float value. Without it, C# will interpret the numbers as double, which can't be automatically converted to either a float or decimal.

Answer 2

The reason for the f after 0.8 is because it's a float number (another Data Type than Double).