Sum of two floats with 2 decimal places resulting in 4 decimal places in JAVA

Question

I am having a JAVA problem where I want to store calculation results with only 2 decimal places in SQL Server. For that at the end of my calculations I perform:

Math.round(valor * 100.0f) / 100.0f;

to obtain the value to two decimal places. After entering the values in the bank I am consulting them and are really only stored with 2 decimal places.

When do I requisition SELECT they are coming with 2 decimal places too.

But the weird thing happens when I try add up two of these values, the result of this sum gives a number with 4 decimal places, follows debug picture:

What could be going on? This rounding is right?

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In addition to making the requisition of INSERT (just to make sure that the value will be entered to 2 decimal places):

INSERT INTO tableX (valor) values (ROUND(?,2))

However it continues to result in a number of 4 decimal places after the sum.

Answer 1

That’s right, that’s because of conversions, and it happens not only in Java, but in many other languages, you’re not doing it wrong.

If you want to format, make calculations or in your case, so it seems to me you are beautiful money, use the format BigDecimal.

Here’s an English thread about this: https://stackoverflow.com/questions/9906169/weird-java-behavior-how-come-adding-doubles-with-exactly-two-decimal-places-res