double

问题 Imagine the following situation. Amounts are added to a total in a loop: float total = 0; float[] amounts = new float[]{...}; foreach(float amount in amounts) { total += amount; } total , as wel as all the amount s are written to a database. When I calculate SUM(amount) in SQL, it results in a value that differs from total . Moreover, when I do the same calculation in C#, but this time adding the amounts to a value of type double, double total = 0; //the rest of the code is the same as above

问题 I am having double value = 30308950000; I want to display it like 3.03x10^10 How can I achieve it using C#? I have tried double value = 30308950000; Console.WriteLine(value.ToString("0.###E+0", CultureInfo.InvariantCulture)); output = 3.03E+10 I dont want the 3.03E+10 format but 3.03x10^10 . Thanks 回答1: Easy fix: double value = 30308950000; Console.WriteLine( value.ToString("0.###E+0", CultureInfo.InvariantCulture) .Replace("E-","x10^-") .Replace("E+","x10^")); Shout out to Jon Skeet! :) 回答2:

问题 I'm trying to make a program to simulate the solar system. for(int i=0;i<1000;i++) { double X=(160*Math.cos((2*PI*i)/365)); double Y=(160*Math.sin((2*PI*i)/365)); posX=Math.round(X); posY=Math.round(Y); cadre.repaint(); sleep(200); } f.setVisible(false); To make my planets turning around the sun, I have a formula; the problem is that i have a double number with this formula, and i can't make him become an int (i tried floor(X), Math.round(X), doesn't work (error : incompatible types :

问题 using System.Numerics; double doubleNumber = Math.Pow(1000, 99); // = 1.0E+297 BigInteger bigBase = (BigInteger)bigNumber; // = 1000000000000000017652801462756379714374878780719864776839443139119744823869255243069012222883470359078822072829219411228534934402712624705615450492327979456500795456339201761949451160807447294527656222743617592048849967890105831362861792425329827928397252374398383022243308510390698430058459037696 Why is the BigInteger value not just 1 kagillion (1,000 followed by a

问题 I am trying to write a program in C to get the percent of even numbers in an array. I am thinking of writing it using int datatype. But some one mentioned to me using double will be easier. I don't understand that. Can anyone guide me with it? What does double datatype return? Can the return statement be given as return (double)? What will that give? Can double convert a real number to a percent? Eg: 0.5 to 50.0 回答1: The int datatype is, as the name would suggest, integers (or whole numbers).

问题 I'm filling an arraylist with some cities, but one of them ("Reggio nell'Emilia") have an apostrophe in its name and when i select it in the app it crashes. Here is the code: SQLiteDatabase db_read = db.getReadableDatabase(); city = new ArrayList<Object>(); Cursor result; for (int i =0 ; i<region.size(); i++) { result = db_read.rawQuery("select distinct city from merchants where region='"+region.get(i)+"' order by city ASC",null); ArrayList<String> cities = new ArrayList<String>(); while

问题 I need to compare an integer in a loop to the quotient of a long and a long . in order to not do integer division, if I understand correctly do I need to convert one of the longs into a double? long prime = primes[d]; int i = 1; // "inputNumber / prime" should not be integer division, while it is now. // How do I do this yet still compare it to an "int" afterwards? while (i < (inputNumber / prime)) { primes[i*prime] = 0; i++; } That's the code snippet. primes is an array filled with long s.

问题 I have a variable of type double X: 1.5 1.3 0.6 1.8 2.9 2.1 1.5 1.4 5.8 0.0 and a vector V: c(0.6,2.9) . I want to remove the values in V from X test<-X[!X %in% V] The values are not removed from test: test [1] 1.5 1.3 0.6 1.8 2.9 2.1 1.5 1.4 5.8 0.0` I tried the following: are.equal <- function(x, y, eps = .Machine$double.eps^0.5) abs(x - y) < eps test=X[!(are.equal(X,0.6))] 0.6 were removed.. I could have something odd in my data or my system. Any idea? 来源： https://stackoverflow.com

问题 I've read a few topics that do already broken down doubles and "puts it together" but I am trying to break it into it's base components. So far I have the bit nailed down: breakDouble( double d ){ long L = *(long*) &d; sign; long mask = 0x8000000000000000L; if( (L & mask) == mask ){ sign = 1; } else { fps.sign = 0; } ... } But I'm pretty stumped as to how to get the exponent and the mantissa. I got away with forcing the double into a long because only the leading bit mattered so truncation

问题 this code works in microsoft visual c++, but when i run this in Xcode, it give me error No member named 'to_string' in namespace 'std' double learningRates[] = {0.00015, 0.00065, 0.00075, 0.0015, 0.0045, 0.0065, 0.0075, 0.055}; long double learning_Value = learningRates[learningRate_Index]; string pathtotal_weight_Bias= pathWeightBias +"/" + "best_weight_Bias" + convertInt(MaxEpochs) +"_LR"+ to_string(learning_Value)+".xml"; even if i used std::to_string(learning_Value), even than it gives