Division in Java always results in zero (0)?

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The question:

The function below gets two values from sharedpreferences, weight and height, and I use these to calculate the BMI,
When I print the content of the values I get the values i have entered in the sharedprefs ( which is good) but then when i run a division operation on them, I always get 0 as a result..
Where is the error?

public int computeBMI(){
    SharedPreferences customSharedPreference = getSharedPreferences(
            "myCustomSharedPrefs", Activity.MODE_PRIVATE);

    String Height = customSharedPreference.getString("heightpref", "");
    String Weight = customSharedPreference.getString("weightpref", "");

    int weight = Integer.parseInt(Weight);
    int height = Integer.parseInt(Height);
    Toast.makeText(CalculationsActivity.this, Height+" "+ Weight , Toast.LENGTH_LONG).show();

    int bmi = weight/(height*height);
    return bmi;

}

The Solutions:

Below are the methods you can try. The first solution is probably the best. Try others if the first one doesn’t work. Senior developers aren’t just copying/pasting – they read the methods carefully & apply them wisely to each case.

Method 1

You’re doing integer division.

You need to cast one operand to double.

Method 2

You are doing an integer division, cast the values to float and change the datatype of the variable bmi to float.

Like this:

float bmi = (float)weight/(float)(height*height);

You should also change the return type of your method public int computeBMI() to float.

I recommend you to read this stackoverflow question.

Here you have a list of the Primitive Data Types in Java with its full description.

Hope it helps!

Method 3

Because bmi is an integer. Either declare bmi or Weight, Height as floating point numbers. When you use integers in a division, you will get integer division. When you use doubles/floats, you will get floating point division


All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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