double

问题 I actually test the casting behavior in C# in unchecked context. Like the documentation said, in unchecked context, the cast always succeed. But sometimes, in particular cases, the cast from one specific type to another type give unexpected result. For example, i tested three "double to sbyte" casts : var firstCast = (sbyte) -129.83297462979882752; // Result : 127. var secondCast = (sbyte) -65324678217.74282742874973267; // Result : 0. var thirdCast = (sbyte) -65324678216.74282742874973267; /

问题 I'm not sure what happened to my old account so had to create this new one. I am having trouble with a batch file I wrote. I have it working where the user will input certain information and then the input will replace text within a file. However, the issue I am having that I couldn't seem to find an answer to exactly on here or help me out is...how do you replace data within quotes? I tried escaping the quotes and i am not sure if it is finding it and just not replacing it or what. Here is

问题 Why are the results of: double a = 0.0/0.0; double b = 0/0.0; = NaN But the results of for example: double e = 0.1/0.0; double e = 12.0/0.0; double f = 1.0/0.0; = Infinity I understand that double or float divisions are somehow a little bit different. I am pretty happy with the resulting NaN because the result is not defined when something is divided by zero. But why they defined that the result of something greater than zero divided by zero is Infitity ? Has this something todo with the

问题 The code below show how to random double in C++11. In this solution each time, when I run this program the result are the same - I don't know why? How to change it to get different solution in every time when I run the program? #include <random> int main(int argc, char **argv) { double lower_bound = 0.; double upper_bound = 1.; std::uniform_real_distribution<double> unif(lower_bound, upper_bound); std::default_random_engine re; double a_random_double = unif(re); cout << a_random_double <<

问题 Simple question, sorry I can;t figure this out. I have some numbers that are made by float(STRING) and they are displayed as xxx.0, but I want them to end in .00 if it is indeed a whole number. How would I do this? Thanks! EDIT: Python saiys that float doesn't have a cal 'format()' 回答1: >>> '%.2f' % 2.0 '2.00' 回答2: Also: >>> "{0:.2f}".format(2.0) '2.00' 回答3: If you do not like the numbers to be rounded, you need to do little more: >>> "%.2f" % 1.99999 '2.00' >>> "%.2f" % (int(1.99999*100)/100

问题 A C program spits out consecutive doubles into a binary file. I wish to read them into Python. I tried using struct.unpack('d',f.read(8)) EDIT: I used the following in C to write a random double number r = drand48(); fwrite((void*)&r, sizeof(double), 1, data); The Errors are now fixed but I cannot read the first value. for an all 0.000.. number it reads it as 3.90798504668055 but the rest are fine. 回答1: I think you are actually reading the number correctly, but are getting confused by the

问题 I want to print a double value to std::cout portably (GCC, clang, MSVC++) such that the output is the same on all platforms. I have a problem with the formatting of the exponent. The following program #include <iostream> int main() { std::cout << 0.1e-7 << std::endl; return 0; } Has this output with GCC: 1e-08 and the following output with MSVC 1e-008 How can I make both outputs the same? I'm sorry if this is a dumb question but I have not found an answer so far. All formatting seems to

问题 I'm using the WPF Extended Toolkit ( http://wpftoolkit.codeplex.com/ ). It has a nice NumericUpDown control that I'd like to use, but internally it uses doubles - which means it uses double.MinValue and double.MaxValue. I'd like to use the same control, but I need a generic version - for ints it needs to use int.MaxValue/MinValue, for floats float.MaxValue/MinValue, etc. (I think you get the idea :)) So I though about copying the NumericUpDown to a GNumericUpDown, where T would ofcourse be

问题 In my application i'm trying to display the bit representation of double variables. It works for smaller double variables. Not working for 10^30 level. Code: #include <iostream> #include <bitset> #include <limits> #include <string.h> using namespace std; void Display(double doubleValue) { bitset<sizeof(double) * 8> b(doubleValue); cout << "Value : " << doubleValue << endl; cout << "BitSet : " << b.to_string() << endl; } int main() { Display(1000000000.0); Display(2000000000.0); Display

问题 Although there are numerous articles about generating permutations, I have an algorithmic need for permutation that's just a bit different. Given a set of elements (a, b, c, .. n) I construct pairs: (ab), (cd), (ef), ... in any combination of elements. Pairs (ab) and (ba) are identical. Also the needed permutations should not be different only in sequence: (ab), (ef), (cd) is identical to (ef), (cd), (ab) As an example, I'll show the exhaustive list of permutations for 6 elements a, b, c, d,