This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 7 years ago.
I have to divide 495/116533, i tried using long and double; but it's returning 0.0;
Once if i able to capture that value (0.004247) then i can use round of methods;
Please help me how to capture complete value( which data type it supports?)
For 4 decimals do:
(double) (Math.round(value * 10000) / 10000)
The number of zeroes is how many decimals you want to round to.
Essentially what you need to do is to first multiply your number by a factor of X so that only the section you want to show is in front of the decimal place, then you can round it using the Math.round function. After that, just divide it back by X in order to put the decimal back in the right spot.
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This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 2 years ago.
I want to round up a double value in java. Always to round up the value in ispite that matematecally correct way, sometimes, is round down the value. For example:
value = 6.5817
I want to round up, keeping two decimals. So I need the value will be like this:
value = 6.59
The important thing here is always keep two decimals and always round up the second decimal if the value have more two decimals.
Have someone idea how I can to do this in java?
Since double values are inexact, e.g. it cannot store a number like 0.07 exactly, you need to use BigDecimal to help round up a double value, with the least probability of getting the wrong value.
To round to 2 decimals, use:
double value = 6.5817;
double roundedUp = BigDecimal.valueOf(value).setScale(2, RoundingMode.UP).doubleValue();
System.out.println(roundedUp); // prints 6.59
Note that this code prints 0.07 when value = 0.07, unlike e.g. Math.ceil(value * 100.0) / 100.0, which incorrectly prints 0.08.
Try the following:
double a = 6.5817;
Math.ceil(a * 100.0) / 100.0;
This question already has answers here:
How to make the division of 2 ints produce a float instead of another int?
(9 answers)
Closed 7 years ago.
This is my array c:
[-33,-22,-11,-5,-4,-3,-2,-1,6,7,8,9,10,11,44,55,66,77,88]
I was able to find the sum by doing this and it worked:
System.out.println(Arrays.stream(c).sum()));
I tried a similar approach to get the average:
System.out.printf("%.2f",(Arrays.stream(c).sum()/c.length));
I got an IllegalFormatConversionException for that though.
When I manually do the average on a calculator, it should come out to 15.78947...but I only want to round 2 places after the decimal. I have tried other statements but those kept giving be 15 as the average and cutting the decimals off. I need to compute the average within the print statement. How can I do this?
I want my output to look like this: 15.79
double average = Arrays.stream(numbers).average().getAsDouble();
This should do the trick.
Arrays.stream(c).sum()/c.length is integer since both arguments are integer.
So you are trying to format Integer as float.
You need explicitly cast one of arguments to float (or double) to get decimal result.
Something like
Arrays.stream(c).sum()/(double)c.length
This question already has answers here:
Division of integers in Java [duplicate]
(7 answers)
Closed 8 years ago.
It's been a long day for me and I don't know if I can't do second grade math or if I'm doing something wrong in terms of how to do math in java. I'm not new to java, I started about a year and a half ago, but like I said, it's been a long day.
Here is my code:
System.out.println(5 / 150 * 100);
I expect to get something like "3.3333" or at least "3", but I get "0" instead. Why is that and how do I fix it?
Your second grade math is perfectly correct. However, 5 / 150 = 0.03 will become zero because its type is int. Then multiplying 0 with 100 won't change anything.
Use floats or doubles and you'll get the right result. Which of these two you use, depends on your needs. If you need a very precise value (a freaking lot of 3s behind the point) use double because it has - as its name tells you - two times the precision of a float.
All of your operand is int value and it will result in int value.
Try to change your operand to float value.
Try this:
System.out.println(5f / 150 * 100);
System.out.println(5 / 150f * 100);
This question already has answers here:
Why does division result in zero instead of a decimal?
(5 answers)
Closed 8 years ago.
I have hit a snag in my program when this calculates I get result of 0.0
y = 1/6*Math.pow(x,3)+1/2*Math.pow(x,2)-1/3*x;
I have tried writing the equation in chunks so I can add the results up after calculation but the result just keeps ending up being 0.0 and I don't know why. Is this a syntactical error or is there a rule that I'm missing about java?.
When you divide two integers Java truncates the result to an integer. If you want a fractional result you need to use floating point numbers. 1/2 is 0; 1.0/2.0 is 0.5.
y = 1.0/6.0*Math.pow(x,3) + 1.0/2.0*Math.pow(x,2) - 1.0/3.0*x;
y = 1/6*Math.pow(x,3)+1/2*Math.pow(x,2)-1/3*x;
Here you are doing division of two integers, which would result in 0. Make one/both of the values to decimal (1.0/6.0 etc) and then try this. It should give the correct result. The reason is that, 1/6 will be corrected to the closest integer value, which is 0.
This question already has answers here:
How to round a number to n decimal places in Java
(39 answers)
Closed 8 years ago.
I'm using float to display decimal numbers, but sometimes it doesn't display correct result.
For example, for 6.2/1000 the result is 0.0061999997.
I know why is this happening, but I wonder is there a way to display correct result, in this case, 0.0062?
EDIT:
How to round a number to n decimal places in Java does not answer to my question, so why did you marked my question as already been answered in other place?
Numbers I wrote are only example. In the app user can enter any number and divide / multiply number with any other number, so the result maybe won't have any decimal points, maybe it will have 4 decimals, maybe it will have 7 decimals,...
First, you need to understand that this isn't just a display issue - if you want to avoid displaying incorrect values, it helps to have the right values to start with.
You should use BigDecimal instead of float. That stores the value as an integer scaled by a factor of 10exp rather than the 2exp used by double and float.
If the BigDecimal.toString doesn't format the result the way you want, use DecimalFormat to perform the formatting instead.
Format the decimal places use this:
DecimalFormat df = new DecimalFormat();
df.setMaximumFractionDigits(decimalPlace);
String formatedValue = df.format(value);
Hope this will resolve your query.