First of all, I assume that you know that 6.2f * 10 is not exactly 62 due to floating point rounding (it’s actually the value 61.99999809265137 when expressed as a double) and that your question is only about why two seemingly identical computations result in the wrong value. The answer is that in the case … Read more
In Java, a – b is never equal to 0 if a != b. This is because Java mandates IEEE 754 floating point operations which support denormalized numbers. From the spec: In particular, the Java programming language requires support of IEEE 754 denormalized floating-point numbers and gradual underflow, which make it easier to prove desirable … Read more
FYI. Carmack didn’t write it. Terje Mathisen and Gary Tarolli both take partial (and very modest) credit for it, as well as crediting some other sources. How the mythical constant was derived is something of a mystery. To quote Gary Tarolli: Which actually is doing a floating point computation in integer – it took a … Read more
When an operation results in a quiet NaN, there is no indication that anything is unusual until the program checks the result and sees a NaN. That is, computation continues without any signal from the floating point unit (FPU) or library if floating-point is implemented in software. A signalling NaN will produce a signal, usually … Read more
THE SIMPLE ANSWER The standard doesn’t allow floating points as non-type template-arguments, which can be read about in the following section of the C++11 standard; 14.3.2/1 Template non-type arguments [temp.arg.nontype] A template-argument for a non-type, non-template template-parameter shall be one of: for a non-type template-parameter of integral or enumeration type, a converted constant … Read more
I can’t help the way it’s stored, but at least formatting works correctly: ‘%.1f’ % round(n, 1) # Gives you ‘5.6’
If your float is always expressed in decimal notation something like >>> import re >>> re.findall(“\d+\.\d+”, “Current Level: 13.4db.”) [‘13.4’] may suffice. A more robust version would be: >>> re.findall(r”[-+]?(?:\d*\.\d+|\d+)”, “Current Level: -13.2db or 14.2 or 3”) [‘-13.2’, ‘14.2’, ‘3’] If you want to validate user input, you could alternatively also check for a float … Read more
Casting to an int will truncate toward zero. floor() will truncate toward negative infinite. This will give you different values if bar were negative.
add 0.5 before casting (if x > 0) or subtract 0.5 (if x < 0), because the compiler will always truncate. float x = 55; // stored as 54.999999… x = x + 0.5 – (x<0); // x is now 55.499999… int y = (int)x; // truncated to 55 C++11 also introduces std::round, which likely … Read more
$rootbeer = (float) $InvoicedUnits; Should do it for you. Check out Type-Juggling. You should also read String conversion to Numbers.