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javaintdoubledivide

Calculation in Java

I have the following calculation in Java:

rightMotor = (int) (((double)speed)/((double)100)*rightMotor));

Speed and rightMotor are both integers. The problem is, it keeps returning 0. I have tried to force to divide speed and 100 as doubles, which had no different results. Can anyone give me some insight in this?

Thanks in advance.

Solution

  • The reason the calculation returns zero is that the double value computed by the expression is less than one.

    It looks like you have placed the parentheses incorrectly - currently, you divide speed by hundred times rightMotor, which is bound to produce a value less than 1.

    You need to fix your formula to make it work. If you wanted to compute speed / 100 * rightMotor as if it were a math formula, you could do the multiplication ahead of division, avoiding doubles altogether:

    rightMotor = speed * rightMotor / 100;