November 9, 1999 - Fuzzy Comparison | WebReference

November 9, 1999 - Fuzzy Comparison

Yehuda Shiran November 9, 1999
Fuzzy Comparison
Tips: November 1999

Yehuda Shiran, Ph.D.
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The equal operator (==) is not suitable for floating point numbers due to inaccuracy issues. Using logical AND and OR operators, you can check if the number is close to the specified value. For example, if you want to evaluate the expression x == 10.0 you need to use a fuzzy comparison using one of the following expressions: 

((x - 10.0) < 0.001) || ((10.0 - x) < 0.001)

or:

(x > (10.0 - 0.001)) && (x < (10.0 + 0.001))