Or even simpler, import java.nio.ByteBuffer; public static byte[] toByteArray(double value) { byte[] bytes = new byte[8]; ByteBuffer.wrap(bytes).putDouble(value); return bytes; } public static double toDouble(byte[] bytes) { return ByteBuffer.wrap(bytes).getDouble(); }
If you want that for display purposes, use java.text.DecimalFormat: new DecimalFormat(“#.##”).format(dblVar); If you need it for calculations, use java.lang.Math: Math.floor(value * 100) / 100;
Am I wrong in assuming it should be faster and more efficient? I’d hate to go through and change everything in a massive program to find out I wasted my time. Short answer Yes, you are wrong. In most cases, it makes little difference in terms of space used. It is not worth trying to … Read more
Update: The answer below still applies in principle, but Swift 4 completed a redesign of the numeric protocols, such that adding your own is often unnecessary. Take a look at the standard library’s numeric protocols before you build your own system. This actually isn’t possible out of the box in Swift. To do this you’ll … Read more
You can’t compare floating point values for equality. See this article on “Comparing floating point numbers” for a discussion of how to handle the intrinsic error. It isn’t as simple as comparing to a constant error margin unless you know for sure what the absolute range of the floats is beforehand.
There are 3 problems. 1) Incorrect decimal separator Different cultures use different decimal separators (namely , and .). If you replace . with , it should work as expected: Console.WriteLine(Convert.ToDouble(“52,8725945”)); You can parse your doubles using overloaded method which takes culture as a second parameter. In this case you can use InvariantCulture (What is the … Read more
I use the following: double x = Math.Truncate(myDoubleValue * 100) / 100; For instance: If the number is 50.947563 and you use the following, the following will happen: – Math.Truncate(50.947563 * 100) / 100; – Math.Truncate(5094.7563) / 100; – 5094 / 100 – 50.94 And there’s your answer truncated, now to format the string simply … Read more
I think this describes solution to your problem: Java Traps: Big Decimal and the problem with double here From the original blog which appears to be down now. Java Traps: double Many traps lay before the apprentice programmer as he walks the path of software development. This article illustrates, through a series of practical examples, … Read more
An explicit cast to double like this isn’t necessary: double trans = (double) trackBar1.Value / 5000.0; Identifying the constant as 5000.0 (or as 5000d) is sufficient: double trans = trackBar1.Value / 5000.0; double trans = trackBar1.Value / 5000d;
I almost never do two queries. Simply return one more row than is needed, only display 10 on the page, and if there are more than are displayed, display a “Next” button. SELECT x, y, z FROM `table` WHERE `some_condition` LIMIT 0, 11 // iterate through and display 10 rows. // if there were 11 … Read more