double

问题 Hello I was wondering if it was possible to store a double into a ghashtable considering there is no gdouble_to_pointer methdod. I am following a tutorial I found online by IBM http://www.ibm.com/developerworks/linux/tutorials/l-glib/section5.html , but I can't seem to find a way to use an int as a key and a double as the value being stored. Any help would be great thanks! 回答1: If you want to use an int as a key, you should use g_int_hash() and g_int_equal() when you create the GHashTable. As

问题 I am trying to parse double values from a single dimension String array. When I attempt to do this, the doubles always parse as 0.0, never as the correct value. Why is this the case? Code: Parser Method: (Ignore integer parser, this one works fine when given an integer) NumReturn numberParser(int cIndex) { // current index of array where num is NumReturn nri; NumReturn nrd; try { nri = new NumReturn(Integer.parseInt(Lexer.token[cIndex]), cIndex++, 'i'); System.out.println(nri.value + " ");

问题 How can I use String.Format in C# so doubles are displayed like this: Values: -1.0 1.011 100.155 1000.25 11000.52221 displayed string: -1.00 1.011 100.2 1000 11001 The main point is my width is fixed to 5 characters no matter what. I don't really care how many decimal places are shown to the right. If there are 4 or more numbers to the left of decimal I want everything right of the decimal to be dropped (including the decimal itself). It seems like something that should be a pretty standard

问题 $(document).ready(function(){ $("#enviar").click(function(e){ e.preventDefault(); //prevent run 2 or more times if the user clicks the button multiple times to send $.post(url,{data:data1,data2:data2},function(rp){ }); }); }); as prevent send 2 times the "post" if the user repeatedly click the button, without disabling the submit button 回答1: Use a special class (e.g : submitting ) as a marker to indicate the request is in progress : $("#enviar").click(function(e){ e.preventDefault(); var btn

问题 I have an ASP.NET DropDownList control that renders into a dropdown list (select HTML tag) on a page. For some reason, when I'm in Internet Explorer, it requires two clicks for me to open it up and see the options, which is just an extra click for the end-user. It works fine in Google Chrome, Mozilla Firefox and Safari--I only have to click once to see the options for a selection. Why would it not work correctly in IE? And more importantly, how can I fix it in IE? Here is my code: <asp

问题 Here's the code: static void Main(string[] args) { int xd2 = 5; for (double xd = (double)xd2; xd <= 6; xd += 0.01) { Console.WriteLine(xd); } } and here's the output: I want to keep on adding 0.01 (as You can see on the screen, sometimes it happens to add 0.99999) Thanks 回答1: Use decimal if you want to keep this kind of accuracy. Floating point types cannot accurately represent certain values. I suggest reading What Every Computer Scientist Should Know About Floating-Point Arithmetic for a

问题 I have a lots of list of strings that look similar to this: list = ['4', '-5', '5.763', '6.423', '-5', '-6.77', '10'] I want to convert it to a list of ints (or doubles) but the - keeps producing an error. 回答1: >>> lst = ['4', '-5', '5.763', '6.423', '-5', '-6.77', '10'] >>> map(float, lst) [4.0, -5.0, 5.763, 6.423, -5.0, -6.77, 10.0] And don't use list as a variable name 回答2: >>> [float(x) for x in ['4', '-5', '5.763', '6.423', '-5', '-6.77', '10']] [4.0, -5.0, 5.763, 6.423, -5.0, -6.77, 10

问题 I have created a Java bean class like this class BeanDemo { private double value; //getter and setter } class myApp { BeanDemo beanDemo=new BeanDemo(); int val=7; if(val<5) { beanDemo.setValue(23.456); } double value=beanDemo.getValue(); // Always returns 0.0 if it is not set System.out.println(value); } How can I check if that value is null? I mean if it is not set I should print something else(say null ) I cannot check if its 0.0 because may be i can set the value to 0.0 also. Thanks 回答1:

问题 I have on question regarding double precision.When a float value is passed into double then I get some different result. For e.g. float f= 54.23f; double d1 = f; System.out.println(d1); The output is 54.22999954223633. Can someone explain the reason behind this behaviour. Is it like double defaults to 14 places of decimal precision. 回答1: The same value is printed differently for float and double because the Java specification requires printing as many digits as needed to distinguish the value

问题 From managed C++, I am calling an unmanaged C++ method which returns a double. How can I convert this double into a managed string? 回答1: I assume something like (gcnew System::Double(d))->ToString() 回答2: C++ is definitely not my strongest skillset. Misread the question, but this should convert to a std::string, not exactly what you are looking for though, but leaving it since it was the original post.... double d = 123.45; std::ostringstream oss; oss << d; std::string s = oss.str(); This