# Floating Point Approximations.

From: David Cressey <cressey73_at_verizon.net>

Date: Wed, 28 Mar 2007 14:28:00 GMT

Message-ID: <QXuOh.4210$5E3.2288_at_trndny01>

Here's another example of floating point errors, that's even simpler than the 21200 plus 2.5% example.

Date: Wed, 28 Mar 2007 14:28:00 GMT

Message-ID: <QXuOh.4210$5E3.2288_at_trndny01>

Here's another example of floating point errors, that's even simpler than the 21200 plus 2.5% example.

int i;

float x = 0;

for (i = 1; i < 100; ++i)

x += 0.01;

x -= 1;

printf (x);

I apologize if I copied the code wrong. The idea is to start with zero, add one hundredth a hundred times, and subtract one. The answer is not quite zero.

Many environments will give a small error. This is such a trivial example that it should make all programmers shudder about using floats, unless they really know what they are doing. Received on Wed Mar 28 2007 - 16:28:00 CEST