Why Shouldn't You Use == to Compare Floats in Java?

Question: Pitfalls of Using == for Float Comparison in Java

Despite its presence as an equality operator for floating-point numbers in Java, == has limitations when comparing floats, as evidenced by static analysis warnings like "JAVA0078 Floating point values compared with ==".

Answer: The Precision Problem

Floating-point numbers are stored as approximations, and rounding errors can occur during operations. Consequently, using == to compare two floats may yield false negatives or positives.

The Correct Approach: Tolerance Margin

The proper approach for comparing floats for "equality" involves testing if the absolute difference between them is smaller than a predefined tolerance value. This ensures that the comparison accounts for rounding errors and matches the intended precision:

Epsilon Value Selection

Selecting an appropriate epsilon value depends on the desired precision. For precise comparisons, smaller epsilon values are used, while larger epsilon values allow for wider margins of error.

The above is the detailed content of Why Shouldn't You Use == to Compare Floats in Java?. For more information, please follow other related articles on the PHP Chinese website!