scientific-notation

问题 I would like to pass the double value received from web page to sqlServer database. the value are wrapped in a value object. public class testVO{ Double value; public Double getValue() { return value; } public void setValue(Double value) { this.value = value; } } However, the problem I've met is when the value is smaller than 0.0001, it will transfer into 1.0E-4 or other scientific-notation, which causes the database error. The way I found is to use BigDecimal.valueOf(testVO.getValue()) to

问题 I'm building a program to to convert double values in to scientific value format(mantissa, exponent). Then I noticed the below 369.7900000000000 -> 3.6978999999999997428 68600000 -> 6.8599999999999994316 I noticed the same pattern for several other values also. The maximum fractional error is 0.000 000 000 000 001 = 1*e-15 I know the inaccuracy in representing double values in a computer. Can this be concluded that the maximum fractional error we would get is 1*e-15 ? What is significant

问题 I have a problem: a number is showing in scientific notation if it has 8 or more digits before the decimal point. Is there a simple way to convert this number to decimal via a library or something? I began creating a manual method to parse it out, but it seems overcomplicated. Any help will be appreciated. input example: 1.0225556677556E7 Edit: I also need to be able to identify a number that is in scientific notation 回答1: You can use NumberFormat your accomplish your goal easily. String

问题 I am trying to read a file that has the following contents: 1.0000000e+01 2.9265380e+03 5.0821200e+02 4.3231640e+01 2.0000000e+01 1.0170240e+04 9.2798610e+02 4.0723180e+01 3.0000000e+01 2.1486260e+04 1.1832420e+03 1.0328000e+01 4.0000000e+01 3.3835080e+04 1.1882285e+03 -9.3307000e+00 5.0000000e+01 4.5250830e+04 1.0899705e+03 -1.0320900e+01 6.0000000e+01 5.5634490e+04 9.8935650e+02 -9.8019000e+00 7.0000000e+01 6.5037960e+04 8.9134700e+02 -9.8000000e+00 but I can't seem to find a proper way to

问题 I am looking for a way to format a floating point number dynamically in either standard decimal format or scientific notation, depending on the value of the number. For moderate magnitudes, the number should be formatted as a decimal with trailing zeros suppressed. If the floating point number is equal to an integral value, the decimal point should also be suppressed. For extreme magnitudes (very small or very large), the number should be expressed in scientific notation. Alternately stated,

问题 On the JSON website here, it explains the different possibilities of JSON 'objects'. However, in the numbers section, these appear: e | e+ | e- | E | E+ | E- 1 - What do these represent? In searching for an answer, <E> appears alot. 2 - Is <E> related to the above e | E s? 回答1: It's the notation JSON (and most programming languages) use for scientific notation. Scientific notation is used to denote very large or small floating-point numbers. The e (or equivalently E ) is equivalent to "×10^".

问题 I'm having difficulty with decimal values that I need to use for arithmetic in some cases and as strings in others. Specifically I have a list of rates, ex: rates=[0.1,0.000001,0.0000001] And I am using these to specify the compression rates for images. I need to initially have these values as numbers because I need to be able to sort them to make sure they are in a specific order. I also want to be able to convert each of these values to strings so I can 1) embed the rate into the filename

问题 I have a file with this format: -0.0064785667 0.73900002 0.028505694 4.7858757e-39 315 218 -0.0051828534 0.73900002 0.028505694 4.6936954e-39 316 218 -0.0038818798 0.73799998 0.028467119 5.1546736e-39 317 218 -0.0025879198 0.73799998 0.028467119 5.6160217e-39 318 218 -0.0012939599 0.73799998 0.028467119 6.4461411e-39 319 218 I read it with this code: using namespace std; ifstream inputFile; //Opens data file for reading. inputFile.open(filePath.c_str()); //Creates vector, initially with 0

问题 I have been working with the PHP code that the expected result will become : 1 101 10001 1000001 100000001 10000000001 1000000000001 100000000000001 10000000000000001 1000000000000000001 finally the output was : 1 101 10001 1000001 100000001 10000000001 1000000000001 // (1 billion) to (100 billion - 1) still showing the actual number, and then 1.0E+14 1.0E+16 1.0E+18 I've found some solutions there! they said by using sprintf or trying format_number . I tried both. using sprintf and the

问题 I want to format a floating point value to n significant digits but never using scientific notation (even if it would be shorter). The format specification %f doesn't deal in significant digits, and %g will sometimes give me scientific notation (which is inappropriate for my use). I want values in the form "123", "12.3", "1.23" or "0.000000123" . Is there an elegant way to do this using C++ or boost ? 回答1: The best way I know (and use it in my own code) is #include <string> #include <math.h>