Questions tagged [double]
Double is a primitive data type used to store fractional numbers that holds a double-precision floating-point (often 64 bits).
double
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Difference between decimal, float and double in .NET?
What is the difference between decimal, float and double in .NET?
When would someone use one of these?
Tom
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7
answers
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decimal vs double! - Which one should I use and when? [duplicate]
I keep seeing people using doubles in C#. I know I read somewhere that doubles sometimes lose precision.
My question is when should a use a double and when should I use a decimal type?
Which type is ...
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806
votes
13
answers
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How to convert Decimal to Double in C#?
I want to assign the decimal variable "trans" to the double variable "this.Opacity".
decimal trans = trackBar1.Value / 5000;
this.Opacity = trans;
When I build the app it gives ...
616
votes
29
answers
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views
How to nicely format floating numbers to string without unnecessary decimal 0's
A 64-bit double can represent integer +/- 253 exactly.
Given this fact, I choose to use a double type as a single type for all my types, since my largest integer is an unsigned 32-bit number.
But now ...
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votes
13
answers
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Round a double to 2 decimal places [duplicate]
If the value is 200.3456, it should be formatted to 200.34.
If it is 200, then it should be 200.00.
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5
answers
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Correct format specifier for double in printf
What is the correct format specifier for double in printf? Is it %f or is it %lf? I believe it's %f, but I am not sure.
Code sample
#include <stdio.h>
int main()
{
double d = 1.4;
printf(&...
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votes
5
answers
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views
Why does Math.round(0.49999999999999994) return 1?
In the following program you can see that each value slightly less than .5 is rounded down, except for 0.5.
for (int i = 10; i >= 0; i--) {
long l = Double.doubleToLongBits(i + 0.5);
...
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552
votes
36
answers
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Rounding a double value to x number of decimal places in swift
Can anyone tell me how to round a double value to x number of decimal places in Swift?
I have:
var totalWorkTimeInHours = (totalWorkTime/60/60)
With totalWorkTime being an NSTimeInterval (double) ...
- 6,659
422
votes
21
answers
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views
Checking if a double (or float) is NaN in C++
Is there an isnan() function?
PS.: I'm in MinGW (if that makes a difference).
I had this solved by using isnan() from <math.h>, which doesn't exist in <cmath>, which I was #includeing at ...
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421
votes
8
answers
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Double vs. BigDecimal?
I have to calculate some floating point variables and my colleague suggest me to use BigDecimal instead of double since it will be more precise. But I want to know what it is and how to make most out ...
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374
votes
9
answers
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352
votes
8
answers
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Round double in two decimal places in C#?
I want to round up double value in two decimal places in c# how can i do that?
double inputValue = 48.485;
after round up
inputValue = 48.49;
Related: c# - How do I round a decimal value to 2 ...
- 9,397
329
votes
14
answers
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views
Convert String to double in Java
How can I convert a String such as "12.34" to a double in Java?
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320
votes
7
answers
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How do you test to see if a double is equal to NaN?
I have a double in Java and I want to check if it is NaN.
What is the best way to do this?
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313
votes
17
answers
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How do I print a double value without scientific notation using Java?
I want to print a double value in Java without exponential form.
double dexp = 12345678;
System.out.println("dexp: "+dexp);
It shows this E notation: 1.2345678E7.
I want it to print it like this: ...
- 3,887
306
votes
11
answers
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views
Biggest integer that can be stored in a double
What is the biggest "no-floating" integer that can be stored in an IEEE 754 double type without losing precision?
In other words, at would the follow code fragment return:
UInt64 i = 0;
...
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301
votes
12
answers
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When should I use double instead of decimal?
I can name three advantages to using double (or float) instead of decimal:
Uses less memory.
Faster because floating point math operations are natively supported by processors.
Can represent a larger ...
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285
votes
19
answers
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How do I parse a string with a decimal point to a double?
I want to parse a string like "3.5" to a double. However,
double.Parse("3.5")
yields 35 and
double.Parse("3.5", System.Globalization.NumberStyles.AllowDecimalPoint)
throws a FormatException.
...
Legate
264
votes
3
answers
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views
How do I convert a string to a double in Python?
I would like to know how to convert a string containing digits to a double.
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255
votes
9
answers
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Float and double datatype in Java
The float data type is a single-precision 32-bit IEEE 754 floating point and the double data type is a double-precision 64-bit IEEE 754 floating point.
What does it mean? And when should I use float ...
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votes
5
answers
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Can't use modulus on doubles?
I have a program in C++ (compiled using g++). I'm trying to apply two doubles as operands to the modulus function, but I get the following error:
error: invalid operands of types 'double' and '...
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votes
12
answers
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Compare double to zero using epsilon
Today, I was looking through some C++ code (written by somebody else) and found this section:
double someValue = ...
if (someValue < std::numeric_limits<double>::epsilon() &&
...
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215
votes
15
answers
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C# Double - ToString() formatting with two decimal places but no rounding
How do I format a Double to a String in C# so as to have only two decimal places?
If I use String.Format("{0:0.00}%", myDoubleValue) the number is then rounded and I want a simple truncate without ...
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207
votes
9
answers
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How to round a Double to the nearest Int in swift?
I'm trying to make a calculator of growth rate (Double) that will round the result to the nearest Integer and recalculate from there, as such:
let firstUsers = 10.0
let growth = 0.1
var users = ...
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206
votes
19
answers
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How do I convert a double into a string in C++?
I need to store a double as a string. I know I can use printf if I wanted to display it, but I just want to store it in a string variable so that I can store it in a map later (as the value, not the ...
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196
votes
3
answers
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Why is a round-trip conversion via a string not safe for a double?
Recently I have had to serialize a double into text, and then get it back. The value seems to not be equivalent:
double d1 = 0.84551240822557006;
string s = d1.ToString("R");
double d2 = double.Parse(...
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votes
24
answers
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views
Retain precision with double in Java
public class doublePrecision {
public static void main(String[] args) {
double total = 0;
total += 5.6;
total += 5.8;
System.out.println(total);
}
}
The above ...
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votes
11
answers
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How to implement infinity in Java?
Does Java have anything to represent infinity for every numerical data type? How is it implemented such that I can do mathematical operations with it?
E.g.
int myInf = infinity; //However it is done
...
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votes
2
answers
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Android - Round to 2 decimal places [duplicate]
Possible Duplicate:
Round a double to 2 significant figures after decimal point
I know that there are plenty of examples on how to round this kind numbers.
But could someone show me how to round ...
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154
votes
3
answers
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Why does adding 0.1 multiple times remain lossless?
I know the 0.1 decimal number cannot be represented exactly with a finite binary number (explanation), so double n = 0.1 will lose some precision and will not be exactly 0.1. On the other hand 0.5 can ...
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151
votes
5
answers
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Converting a double to an int in C#
In our code we have a double that we need to convert to an int.
double score = 8.6;
int i1 = Convert.ToInt32(score);
int i2 = (int)score;
Can anyone explain me why i1 != i2?
The result that I get ...
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146
votes
20
answers
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How to get the Power of some Integer in Swift language?
I'm learning swift recently, but I have a basic problem that can't find an answer
I want to get something like
var a:Int = 3
var b:Int = 3
println( pow(a,b) ) // 27
but the pow function can work ...
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144
votes
15
answers
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Scala Doubles, and Precision
Is there a function that can truncate or round a Double? At one point in my code I would like a number like: 1.23456789 to be rounded to 1.23
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143
votes
16
answers
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Swift double to string
Before I updated xCode 6, I had no problems casting a double to a string but now it gives me an error
var a: Double = 1.5
var b: String = String(a)
It gives me the error message "double is not ...
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votes
3
answers
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Converting double to integer in Java
In Java, I want to convert a double to an integer, I know if you do this:
double x = 1.5;
int y = (int)x;
you get y=1. If you do this:
int y = (int)Math.round(x);
You'll likely get 2. However, I ...
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140
votes
3
answers
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Why does this random value have a 25/75 distribution instead of 50/50?
Edit: So basically what I'm trying to write is a 1 bit hash for double.
I want to map a double to true or false with a 50/50 chance. For that I wrote code that picks some random numbers (just as an ...
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139
votes
13
answers
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Double decimal formatting in Java
I'm having some problems formatting the decimals of a double. If I have a double value, e.g. 4.0, how do I format the decimals so that it's 4.00 instead?
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votes
5
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Dealing with float precision in Javascript [duplicate]
I have a large amount of numeric values y in javascript. I want to group them by rounding them down to the nearest multiple of x and convert the result to a string.
How do I get around the annoying ...
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votes
13
answers
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Round up double to 2 decimal places
How do I round up currentRatio to two decimal places?
let currentRatio = Double (rxCurrentTextField.text!)! / Double (txCurrentTextField.text!)!
railRatioLabelField.text! = "\(currentRatio)"
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Rounding a double to turn it into an int (java)
Right now I'm trying this:
int a = round(n);
where n is a double but it's not working. What am I doing wrong?
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answers
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Why does dividing two int not yield the right value when assigned to double?
How come that in the following snippet
int a = 7;
int b = 3;
double c = 0;
c = a / b;
c ends up having the value 2, rather than 2.3333, as one would expect. If a and b are doubles, the answer does ...
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votes
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answers
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Is it possible to get 0 by subtracting two unequal floating point numbers?
Is it possible to get division by 0 (or infinity) in the following example?
public double calculation(double a, double b)
{
if (a == b)
{
return 0;
}
else
{
...
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132
votes
10
answers
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MySQL pagination without double-querying?
I was wondering if there was a way to get the number of results from a MySQL query, and at the same time limit the results.
The way pagination works (as I understand it) is to first do something like:
...
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votes
7
answers
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Force point (".") as decimal separator in java
I currently use the following code to print a double:
return String.format("%.2f", someDouble);
This works well, except that Java uses my Locale's decimal separator (a comma) while I would like to ...
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126
votes
11
answers
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Convert float to double without losing precision
I have a primitive float and I need as a primitive double. Simply casting the float to double gives me weird extra precision. For example:
float temp = 14009.35F;
System.out.println(Float.toString(...
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How can I truncate a double to only two decimal places in Java?
For example I have the variable 3.545555555, which I would want to truncate to just 3.54.
- 1,417
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5
answers
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How to print a double with two decimals in Android? [duplicate]
Maybe this is a silly question, but I cannot guess how to solve it if it's not creating a method. Maybe there's a "natural way" to do it, like in C for example. Here's the problem:
I have a var:
...
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C# 6 how to format double using interpolated string?
I have used interpolated strings for messages containing string variables like $"{EmployeeName}, {Department}". Now I want to use an interpolated string for showing a formatted double.
...
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votes
7
answers
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In java, is it more efficient to use byte or short instead of int and float instead of double?
I've noticed I've always used int and doubles no matter how small or big the number needs to be. So in java, is it more efficient to use byte or short instead of int and float instead of double?
So ...
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votes
1
answer
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Set precision of std::to_string when converting floating point values [duplicate]
In C++11, std::to_string defaults to 6 decimal places when given an input value of type float or double. What is the recommended, or most elegant, method for changing this precision?
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