float value equation

[dark ninjuh]

Hello. there seems to be a slight bug somewhere in my program (slight bug by .000001 to be precise)

I've been trying to think of a logical equation to solve this but i just cant wrap my head around it.

so this is the problem.

somewhere something is changing my float value by just a little so that it prints things like .599999 or .699999 and .799999 well you get it.
i need to check the numbers to make them correct somehow.

now one method i could use and would work would be like this (not sure if correct syntax, have not had to do this kind of if in quite a while)

if(x>.01 && x<.02){
x = .02;
}
else if (x>.02 && x<.03){
x = .03;
}

ext.. ext...

but as a programmer I'm supposed to find logical ways to not have to repeatedly type so much. what other ways can i solve this problem?

[Yanson]

floats cant accurately represent all numbers which means the computer will sometimes round the number to get the next closest number. leaving you with numbers like .599999999

this is a problem when dealing with money so some programmers will convert a float to two integers. One integer to represent the dollars part and one to represent the cents part.

another way is to check that the float is within a certain rage usually called epsilon this is similar to what you are doing. epsilon being a very small number if the float in question is less than float + epsilon and greater than float - epsilon then its considered ok.

I believe that libraries such as boost have classes that can accurately represent numbers and this is probably what most professional programmers would use.

[QWERTYman]

One way you could solve this--maybe not the best--would be:

for(float i = 0; i < 1; i+= 0.01) //change the definition/inequality to suit values for x
{
    if(x > i && x < i+0.01)
        x = i+0.01;
}

A better solution might be possible, but I'd have to see the context--i.e. what modifies the float value.

[dark ninjuh]

its a double buffered key input in opengl. once its hit it outputs the x value (same issues with the Y) of the location of my tested object to the console. its only adding or subtracting .10 at a time . being why i didn't understand why it occurred. then the console is throwing me numbers that would confuse the average user of my program. if you really wanted to look into it i don't mind sharing details just don't know if thats something you actually would want to look into. its just a simple opengl app that displays an object with the options of movement/rotation.