Interesting problem in C

[abhimanipal]

Hi All,
Today I came across a peculiar piece of code.

int main(int argc, char* argv[])
{
         printf("%lf\n",(0.99-0.90-0.09));

}

According to me the output for this code should be 0, but to my surprise when I ran this code the answer that I got was -0.000.
I cannot understand the reason for the minus sign

[gerard4143]

Try this:

int main(int argc, char* argv[])
{
         printf("%lf\n",(0.99F - 0.90F - 0.09F));

}

[WaltP]

You are dealing with floating point numbers. .99 probably is stored as a close approximation of .99, very close. But not close enough. Same with all the other values. Therefore, you have a little wiggle in the values and probably end up with something similar to -0.000000001 as an answer.

[Salem]

If you want to know more about what WaltP said, then

A short intro:
http://www.randelshofer.ch/fhw/gri/float.html

The long and gory details:
http://docs.sun.com/source/806-3568/ncg_goldberg.html

[abhimanipal]

Got it ... Thanks guys