在Java中四舍五入结果

Question

Hello i am making a program that computes the frequency distribution and i have a problem in getting the number of class because I am going to use this in frequency distribution... the result of # of class is...

6.286797971382275 and it is correct but...

i want to round this off to 7...

how am i going to do that? thanks

    String []values = ( inputValues.getText().toString().split(","));
            int[] convertedValues = new int[values.length];
            txtTotalNum.setText(Integer.toString(values.length));


            //calculate for the minimum and maximum number
            Arrays.sort(convertedValues);

            int max=convertedValues[0];
            for(int i=0;i<convertedValues.length;i++){
                convertedValues[i] =Integer.parseInt(values[i]);
                if(convertedValues[i]>max){
                    max=convertedValues[i];
                }
            }

            int min = convertedValues[0];
             double classes=0;
            for(int i=0;i<convertedValues.length;i++){
                convertedValues[i] =Integer.parseInt(values[i]);
                if(convertedValues[i]<min){
                    min=convertedValues[i];

                }
            }

            txtMinimum.setText(Integer.toString(min));
            txtMaximum.setText(Integer.toString(max));


            //calculate for the range

            int range=max - min;
            txtRange.setText(Integer.toString(range));

            //calculate for the # of classes

                classes=1+3.3*Math.log10(convertedValues.length);

              Classes.setText(Double.toString(classes));

Answer 1

Use Math.ceil()

Math.ceil(6.286797971382275);

This is what it is going to return you,

The smallest (closest to negative infinity) floating-point value that is greater than or equal to the argument and is equal to a mathematical integer.

Read the API before using it.

Answer 2

Consider the Math class.

Math.ceil()

Answer 3

Simply use Math.ceil() . It will round up your number to the nearest whole value. Note, it still returns a double.

Answer 4

Use below code. double dval = 6.286797971382275 ; System.out.println(dval); System.out.println(Math.ceil((dval)));

Answer 5

You can use DecimalFormat beside Math.ceil()

double input = 6.286797971382275;
DecimalFormat df = new DecimalFormat("#");

df.setRoundingMode(RoundingMode.UP);
String output = df.format(input);

System.out.println("output  : " + output);