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javamathdivisioninteger-division

Why does dividing a float by an integer return 0.0?

So if I have a range of numbers '0 - 1024' and I want to bring them into '0 - 255', the maths would dictate to divide the input by the maximum the input will be (1024 in this case) which will give me a number between 0.0 - 1.0. then multiply that by the destination range, (255).

Which is what I want to do!

But for some reason in Java (using Processing) It will always return a value of 0.

The code would be as simple as this

float scale;
scale = (n/1024) * 255;

But I just get 0.0. I've tried double and int. all to no avail. WHY!?

Solution

  • It's because you're doing integer division.

    Divide by a double or a float, and it will work:

    double scale = ( n / 1024.0 ) * 255 ;

    Or, if you want it as a float,

    float scale = ( n / 1024.0f ) * 255 ;