Java float / double subtract

Asked Dec 18 '17 at 23:19

Active Dec 19 '17 at 00:00

Viewed 39 times

I want to make simple subtract operation on float so that I don't get a final decimal but I got same result with float

Better than my bad english : code !

    private double test(final double reloadingTime) {
    double timeRestant = reloadingTime - 0.1;
    System.out.println(timeRestant);
    return timeRestant;
}

main :

    double test = test(2f);
    test = test(test);
    test = test(test);
    test = test(test);
    test = test(test);
    test = test(test);

console :

1.9
1.7999999999999998
1.6999999999999997
1.5999999999999996
1.4999999999999996
1.3999999999999995

So two questions: Why? And how can I can get the true result?

edited Dec 19 '17 at 00:00

sfjac

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asked Dec 18 '17 at 23:19

fabiitch

1

Fundamentally, if you want to use exact *decimal* values, use `BigDecimal`. – Jon Skeet Dec 18 '17 at 23:21
Also make sure to use BigDecimal(String) constructor. – whatamidoingwithmylife Dec 18 '17 at 23:22

Java float / double subtract

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