Android - Float - Always 00 after point

Question

I want to display the average number in the textview. however, the output is always the integer. For example, my input num1 is 2 and 3. the output is 2.00. input: 2 and 7, the output is 4.00.

here is my code.

    <string name="ave">Average: %1$.02f</string> //in strings.xml        

    //in main function
    int num1 = Integer.parseInt(number1.getText().toString());
    int num2 = Integer.parseInt(number2.getText().toString());

    //get the average number
    float average = ( num1 + num2 ) / 2;
    ave_num.setText(getString(R.string.ave, average));

forpas · Accepted Answer · 2018-11-26T12:29:37.640

1

The right side of this assignment:

float average = (num1 + num2) / 2;

consists only of integers.
So after the addition, the division will give the result of integer division.
This is how the compiler treats mathematical operations between integers.
Of course you want the result as float.
So do this:

float average = 1.0f * ( num1 + num2 ) / 2;

By multiplying with 1.0f (the f suffix denotes float) you will get the desired float result.
Or:

float average = ( num1 + num2 ) / 2f;

edited Nov 26 '18 at 12:29

answered Nov 26 '18 at 12:22

forpas

160,666
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1.0f* is work! thanks a lot! – 田睿霖 Nov 27 '18 at 02:07

score 0 · Answer 2 · answered Nov 26 '18 at 12:10

0

Use DecimalFormat

  float average = ( num1 + num2 ) / 2;
  DecimalFormat df = new DecimalFormat();
  df.setMaximumFractionDigits(2);

  System.out.println(df.format(average ));

or String.format

  String average=String.format("%.02f", average )

answered Nov 26 '18 at 12:10

sasikumar

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That won't help because the real problem is integer division, not the formatting – Mark Rotteveel Nov 28 '18 at 09:19

score 0 · Answer 3 · edited Nov 28 '18 at 10:12

0

I've already tested this code:

float average = ( num1 + num2 ) / 2f;

edited Nov 28 '18 at 10:12

Sreeram TP

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answered Nov 26 '18 at 13:14

Hassan Kazemy

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1

score -1 · Answer 4 · answered Nov 26 '18 at 12:10

-1

double roundTwoDecimals(double d)
{
    DecimalFormat twoDForm = new DecimalFormat("#.##");
    return Double.valueOf(twoDForm.format(d));
}

or

String.format("Value of a: %.2f", a) // for 2 decimal number ex. 1.03

String.format("Value of a: %.3f", a) // for 3 decimal number ex. 1.003

String.format("Value of a: %02d", a) // for 2 didgit ex. 01

answered Nov 26 '18 at 12:10

Vinesh Chauhan

1,288
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That won't help because the real problem is integer division, not the formatting – Mark Rotteveel Nov 28 '18 at 09:20

Android - Float - Always 00 after point

4 Answers4