double

问题 What is the biggest "no-floating" integer that can be stored in an IEEE 754 double type without losing precision ? 回答1: The biggest/largest integer that can be stored in a double without losing precision is the same as the largest possible value of a double. That is, DBL_MAX or approximately 1.8 × 10 308 (if your double is an IEEE 754 64-bit double). It's an integer. It's represented exactly. What more do you want? Go on, ask me what the largest integer is, such that it and all smaller

问题 In my C++ project I frequently encounter inexact results due to numerical errors. Is it somehow possible to somehow redefine the standard comparison operators ( == , <= , >= , < , > ) so that they do not compare exactly but within an acceptable error (e.g. 1e-12 ) ? (If yes, is it a good idea to do this?) (Of course one could write comparison functions but people intuitively use the operators.) 回答1: To overload operators some argument must be user-defined type. The built-in ones are fixed and

问题 I have many java projects and I would like to find the double arithmetic operations (+, -, *, /) in my entire code. For example, I want to find a + b line from the below code. Once the code returns all the results, I will manually change them to some APIs. Any one has any idea how to write a program which returns all of such usages? The code to find the below results doesn't necessarily to be written java. I didn't find this question in stackoverflow or in google, please post it if you find

问题 I'm doing some large number divisions (long/long to double, and int/int to float).. But I bump, to a problem when the results include the "E". I know we can use NumberFormat to format when displaying, but that's not what I. Just want the result of the divisions to not involve the "E", i.e. just round it up to the closest float/double that fits in the space. Anybody got an idea? 回答1: The internal representation of floating point number does not have a switch for E presence or not (check IEEE

问题 How to get the sum of Doubles that where parsed from a JTable ? I'm Building a Client/Server Application, and I'm Stuck on a Little issue. I want get the sum of values of a column in a JTable , this column contains String objects with #,## format, so when I try to parse them into doubles with a loop I get this error: java.lang.NumberFormatException: For input string: "0,55" Here is the JTable image: And here is the code that I tried so far: private void jButton10ActionPerformed(java.awt.event

问题 I have a MySQL database with the table " Products ". A column in " Products " is called " Price " and has the datatype " double ". I need to retrieve the values from that column, so I create a reader, etc.: MySQLCommand cmd = new MySQLCommand("SELECT Price FROM Products", connection); MySQLDataReader reader = cmd.ExecuteReaderEx(); if (reader.HasRows == true) { while (reader.Read() == true) { price = reader["Price"]).ToString(); } } Problem is that price isn't set to the expected value. If

问题 I have given two number a and b .I have to Calculate (a^b)%1000000007 .How Can i calculate for floating point numbers. Ex: a= 7.654 and b=10000 Here is my Code will % work : public static double super_pow(double A , long B){ double o=1; while(B>0){ if((B&1)!=0) o*=A; A*=A; B/=2; o%=mod; A%=mod; } return (o)%mod; } 回答1: In java you can use the modulo operation for floats/doubles (How do I use modulus for float/double?) If you have to calculate (a^b)%1000000007 you can use double for a and b

问题 It is ok to do this? double doubleVariable=0.0; if (doubleVariable==0) { ... } Or this code would suffer from potential rounding problems? 回答1: Nope it's perfectly legal if you are only going to compare against 0 as the right side of comparison will automatically casted to double. On the other hand, it would yield all the round-off errors if you where to compare against == 0.10000001 You are better or reading the discussion about float to 0 comparison here: Is it safe to check floating point

问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: How to resolve a Java Rounding Double issue Please Help, I programm some calculator in Java. I use double type. Double has 15 digits after the decimal point. I have problem with the following: 1/3 * 3 = 0.9999999999999999 I need 1/3 * 3 = 1 How can I solve this problem? I keep result in Double. The same problem I have with other mathematical operations, for example sqrt(6) = 2.449489742783, and next I square the

问题 I have read a file containnig numbers including decimal ones e.g.: 10.4 into an array of strings. I want to obtain an array of doubles. My method work for numbers without the decimal part only, but for decimal ones gives following error: An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll Additional information: Input string was not in a correct format. Would you have some ideas how to modify the code to work for all positive real numbers? string[] lines = System