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kiarocks
kiarocks wrote ...

2011/11/8

Wrong Answer to a problem?

kiarocks kiarocks

2011/11/8

#
I wanted to do a problem(math) in greenfoot with this code:
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public int getRemainder(int i, int i2)
    {
        double i3 = (i / i2);
        i3 = i3 * 100;
        int i33 = (int) i3;
        return i33;
    }
Unfortunately, when inputted with values of 40 and 100, it gives 0. Why is this happening? Note: I tried this with a calculator. It gives 40
nccb nccb

2011/11/8

#
When you do i / i2 in the first line of the method, you are dividing an int by an int, which is therefore an integer division. 40/100 is 0 (integer division rounds down). So then the end result is zero. If you add a cast (the numerator is enough) to double, then you will do a double division, resulting in 0.4 (or rather, the nearest number representable: 0.4 cannot be exactly represented in binary), and it will all work out. Long story short, this should fix it:
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double i3 = ((double)i / i2);
danpost danpost

2011/11/9

#
Another way to handle this is simply
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public int getRemainder(int i, int i2)
{
    return (i % i2);
}
This will always return the remainder portion of the division. As short as this is, dropping the method and using (i % i2) in the calling method might be preferable.
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