is there a possibility that casting a double created via Math.round() will still result in a truncated down number No, round() will always round your double to the correct value, and then, it will be cast to an long which will truncate any decimal places. But after rounding, there will not be any fractional parts … Read more
Because Convert.ToInt32 rounds: Return Value: rounded to the nearest 32-bit signed integer. If value is halfway between two whole numbers, the even number is returned; that is, 4.5 is converted to 4, and 5.5 is converted to 6. …while the cast truncates: When you convert from a double or float value to an integral type, … Read more
The rounding error is not random and the way it is implemented it attempts to minimise the error. This means that sometimes the error is not visible, or there is not error. For example 0.1 is not exactly 0.1 i.e. new BigDecimal(“0.1”) < new BigDecimal(0.1) but 0.5 is exactly 1.0/2 This program shows you the … Read more
You can use String.format(“%.2f”, d), your double will be rounded automatically.
double supports Infinity double inf = Double.POSITIVE_INFINITY; System.out.println(inf + 5); System.out.println(inf – inf); // same as Double.NaN System.out.println(inf * -1); // same as Double.NEGATIVE_INFINITY prints Infinity NaN -Infinity note: Infinity – Infinity is Not A Number.
As others have mentioned, you’ll probably want to use the BigDecimal class, if you want to have an exact representation of 11.4. Now, a little explanation into why this is happening: The float and double primitive types in Java are floating point numbers, where the number is stored as a binary representation of a fraction … Read more
I found the bug. .NET does the following in clr\src\vm\comnumber.cpp: DoubleToNumber(value, DOUBLE_PRECISION, &number); if (number.scale == (int) SCALE_NAN) { gc.refRetVal = gc.numfmt->sNaN; goto lExit; } if (number.scale == SCALE_INF) { gc.refRetVal = (number.sign? gc.numfmt->sNegativeInfinity: gc.numfmt->sPositiveInfinity); goto lExit; } NumberToDouble(&number, &dTest); if (dTest == value) { gc.refRetVal = NumberToString(&number, ‘G’, DOUBLE_PRECISION, gc.numfmt); goto lExit; } DoubleToNumber(value, … 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
// The C way: char buffer[32]; snprintf(buffer, sizeof(buffer), “%g”, myDoubleVar); // The C++03 way: std::ostringstream sstream; sstream << myDoubleVar; std::string varAsString = sstream.str(); // The C++11 way: std::string varAsString = std::to_string(myDoubleVar); // The boost way: std::string varAsString = boost::lexical_cast<std::string>(myDoubleVar);
There is a round available in the Foundation library (it’s actually in Darwin, but Foundation imports Darwin and most of the time you’ll want to use Foundation instead of using Darwin directly). import Foundation users = round(users) Running your code in a playground and then calling: print(round(users)) Outputs: 15.0 round() always rounds up when the … Read more