Thread: zero in c

I am implementing a while loop where a float variable changes value several times. I want the loop to stop when the value of the variable reaches 0. I included this line in my code:
while ( (f(c)!=0) && (ABS((b-a)/b)>=0.000005) )
It complies, but when it executes it keeps going longer than it should (i.e. it terminates when the 2nd condition is false. it should terminate before that--when the 1st condition becomes false).

Is there anyway that I can change my while statement to make my program run better.
I've tried using "f(c)!=0.00000" since the variable is a float, but this doesn't work either.

Please help.

You can't compare floats for equality

Try something like this

Code:

do {
   // some calcs
} while ( fabs((b-a)/b) > 0.00001 );

This should terminate the loop when the answer is 'close enough'. It's up to you to define what close enough is.

But bear in mind that floats have only 6 digits of precision, which means you can't compare very large numbers with very small numbers effectively.