This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 3 years ago.
I am using Math.round(). This is the sample code:
double value = 0.14499999970197677;
value = Math.round( value* 100.0) / 100.0;
My expectation is it should return 0.15 but it is returning 0.14
Also, if the value is 0.13499999970197677, then it is returning 0.13, why not 0.14
I have already gone through the link round up to 2 decimal places in java?
Please tell me clearly that why this is happening with both the numbers?
In Java, Math.round rounds up/down to closest long value (in mathematics terms, closest whole number).
14.49 will be rounded to 14 (because it is treated as 14.4). It won't take the .09 into account.
Related
This question already has answers here:
Java Round up Any Number
(7 answers)
Closed 1 year ago.
I want to round a number up even if it is less than 0.5.
In java, for example using the Math.round() it rounds up 0.5 to 1 while rounds down 0.4 to 0.
I want 0.4 also to be rounded up to 1.
Expected Outcomes:
Input : 1.2, Output : 2
Input 1.1, Output : 2
Ceiling
Use Math.ceil( 0.4 ). The name is ceiling, not rounding.
This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 2 years ago.
double1 = .05100000000003;
double2 = .05295;
How do I round a decimal to three places? Respectively, I'd like the output to do this 0.051 and 0.053.
I tried Math.round(double1); but I got back 0.0.
Any ideas would be greatly appreciated thanks.
Try the following code in Java. The number of zeros indicates how many decimal places you would like to round to. (In this case there are 3 zeros).
(double)Math.round(value * 1000d) / 1000d
EDIT: same answer is provided in this previous StackOverflow Post
This question already has answers here:
Is floating point math broken?
(31 answers)
How to resolve a Java Rounding Double issue [duplicate]
(13 answers)
Closed 3 years ago.
I am using math.round() to round off.
this is the code:
double value=0.145
Math.round( value* 100.0) / 100.0;
My expectation is it should return 0.15 but it is returning 0.14.
Also, if the value is 0.055, then it is returning 0.05 instead of 0.06
I have already gone through the link round up to 2 decimal places in java?
Please tell me specific that why this is happening?
Thanks in Advance.
You may use Math.ceil(0.145) to get your desired result 0.15.
If you would print value * 100.0, you would find that this is not actually 14.5 as you would expect, but it's close to 14.499999999999998 (on my jdk1.8.0_181). As you can see, it would give you 0.14 as final result.
Why it happened, this is how floating point arithmetic is supposed to work. When you have a value that cannot be properly represented by binary system, you will face this problem. I am giving links to answers that gives good information why it happens.
https://stackoverflow.com/a/1089026/841221
https://stackoverflow.com/a/8604224/841221
EDIT : Update 1
As matt suggested, it's actually 0.145 which cannot be represented by binary properly. As per IEEE754 Double Precision 64-Bit representation, it's actually is 1.44999999999999990007992778374E-1 which is not exactly 0.145.
This question already has answers here:
Strange floating-point behaviour in a Java program [duplicate]
(4 answers)
Closed 8 years ago.
I want to know the reason why i am getting so many decimal points while doing this sum of double numbers
System.out.println(Double.parseDouble(".56"));
double dvalue=1.12+Double.parseDouble(".56");
System.out.println(dvalue);
output is as follows
0.56 and
1.6800000000000002
why second summation is adding those decimals it should simply 1.68
It's because the addition of the doubles 1.12 and 0.56 does not yield an exact representation of 1.68 (it doesn't precisely result in 1.68). You can see the difference with this code:
System.out.println(1.12+0.56); // 1.6800000000000002
System.out.println(1.68); // 1.68
This question already has answers here:
Int division: Why is the result of 1/3 == 0?
(19 answers)
Dividing by 100 returns 0
(6 answers)
Closed 9 years ago.
Would someone mind explaining why this doesn't work? All variables except for chance are ints, whereas chance is a double. When I print all the values they are definitely correct... but chance always comes out as 0.0. I know this has something to do with converting ints to doubles, as I have had an issue like this a couple of times before. What is the key to getting it to do what you want?
gladValue = (glad.dexterity+glad.tactical+weaponSkill);
oppValue = (glad.target.dexterity+glad.target.tactical+glad.target.agility);
chance = (gladValue/oppValue)*10.0;
Thanks
You should write gladValue * 10.0 / oppValue instead.
The reason is quite subtle. Your brackets mean that gladValue / oppValue is computed first. But these variables are integers so the result is an integer and therefore you lose the fraction part. Only when it is multipled by 10.0 will it get promoted to a double; but by then it's too late.
If you do as I say then, bearing mind that * and / have the same precedence and the operations happen from left to right, then when computing gladValue * 10.0, gladValue is promoted to floating point and that floating point result is divided by oppValue.