How do you see if a 'float variable' is positive or negative?

c as float
a as float = 200: b as float = 500
c = a - b

I know 'c' is a negative variable in this example, and I can print (c) to find out; and I can look at it and know instantly that 'c' is negative.

But when my program is running, it needs to know when a variable is positive or negative. And I need to add it to my code,

because sometimes 'c' will be negative, and other times 'c' will be positive.

I could code 'if c<0' but then my code would be more complicated. So is there a more efficient way to code it?