A sample code using Java double produces surprising results.
UNEXPECTED Result: 0.1d + 0.2d - 0.3d = 5.551115123125783E-17
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| public class DoubleDemo { | |
| // We see UNEXPECTED Result: 0.1d + 0.2d - 0.3d = 5.551115123125783E-17 | |
| private static void demo() { | |
| double problematicRealNumber = 0.1d + 0.2d - 0.3d; | |
| if (problematicRealNumber == 0) | |
| System.out.println("EXPECTED Result: 0.1d + 0.2d - 0.3d =" + 0); | |
| else | |
| System.out.println("UNEXPECTED Result: 0.1d + 0.2d - 0.3d = " + problematicRealNumber); | |
| } | |
| public static void main(String[] args) { | |
| demo(); | |
| } | |
| } |
Same code using Java float does not.
EXPECTED Result: 0.1d + 0.2d - 0.3d = 0
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| // We see EXPECTED Result: 0.1f + 0.2f - 0.3f = 0 | |
| public class FloatDemo { | |
| private static void demo() { | |
| float realNumber = 0.1f + 0.2f - 0.3f; | |
| if (realNumber == 0) | |
| System.out.println("EXPECTED Result: 0.1f + 0.2f - 0.3f = " + 0); | |
| else | |
| System.out.println("UNEXPECTED Result: 0.1f + 0.2f - 0.3f = " + realNumber); | |
| } | |
| public static void main(String[] args) { | |
| demo(); | |
| } | |
| } |
Below is the first of a couple of videos to follow on floating point numbers