我的单独方法不断返回错误的值

Question

I'm using my weight as a value of 180 to find my weight in lbs on planets other than earth with a formula to find weight using mass and surface gravity. The problem I'm facing is that whenever I call this method, the weight value returns as 180 all 8 times the method is called. In my code I have weight being calculated with (mass * roundedSG)/433... It shouldn't return as 180. I don't know how to fix this, I've been trying for a couple hours. The for loop is in a different method, I'm doing this for home work by the way, any help would be appreciated to just try and fix this problem of mine. Thanks!

public static double weight(double sGravity, double w) 
{
    double roundedSG = sGravity / 10;
    double mass = (w * 433.59237)/roundedSG;
    double weight = (mass * roundedSG)/433.59237;

    return weight;
}

    for(int i = 0; i < planetSurfaceGravity.length; i++)
    {
        weightOnPlanets[i] = weight(planetSurfaceGravity[i], weightLbs);
        System.out.println(weightOnPlanets[i]);
    }
}

Answer 1

I think your math in weight() is incorrect. It looks like weight is actually returning the following:

 (w * 433/roundedSG)*roundedSG/433.

The 433s and roundedSGs cancel, and you're just returning w, which I'm guessing is 180?

Answer 2

Correct Weight Formula is:

weight = (mass*gravity);

Change from:

 double weight = (mass * roundedSG)/433.59237;

To:

double weight = mass * roundedSG;

Answer 3

You weight method calculation are incorrect. the result of it returns only w which you pass as weightLbs (= 180).

Answer 4

I renamed your variables and added a constant which makes the code as written a bit clearer:

private static final double GRAMS_PER_POUND = 433.59237;
public static double weight(double sGravity, double weightLbs)  
{
    double roundedSG = sGravity / 10;
    double mass = (weightLbs * GRAMS_PER_POUND)/roundedSG;
    double weight = (mass * roundedSG)/GRAMS_PER_POUND;

    return weight;
}

So your mass on earth, which is converted to grams, is being divided by the gravity of whatever planet you're checking. Change the mass calculation to be

double mass = weightLbs * GRAMS_PER_POUND;

Then the weight calculation should be ok as is, returning the weight on the other planet converted back from grams to pounds.