java - 尝试输出数学方程的解总是结果为 0

Question

我是 Java 和编码的完全初学者，我正在尝试制作一个程序，根据用户输入到程序中的内容来求解两个方程。我试过将变量类型更改为 long、int、double，但没有任何变化。结果始终为 0 或 0.0 任何帮助将不胜感激。

package pa2;
import java.util.Scanner;
public class GravitationalForce 
{
    public static void main(String[] args) 

        {
            System.out.println("Please enter the name of the planet and its weight in quintillion kilograms");
            Scanner myScanner = new Scanner (System.in);
            String planetName = myScanner.next();
            int planetWeight = myScanner.nextInt();

            System.out.println("Enter the weight of the person in kilograms");
            double personWeight = myScanner.nextDouble();

            System.out.println("Please enter the radius of the planet Alderaan in million meters");
            double planetRadius = myScanner.nextDouble();
            Long gravitationalConstant = (long) (6.673*Math.pow(10,-11));
            Double force = gravitationalConstant*(planetWeight*Math.pow(10, 18)*personWeight)/planetRadius*Math.pow(10, 6)*planetRadius*Math.pow(10, 6);
            Double gravity = gravitationalConstant*(planetWeight*Math.pow(10, 18)/planetRadius*Math.pow(10, 6)*planetRadius*Math.pow(10, 6));

            System.out.println("The gravitational force of planet " + planetName + " on the person is " + force + " Newtons");
            System.out.println("The gravity of the planet " + planetName + " is " + gravity + " meters per second squared");
        }
}

Answer 1

6.673*Math.pow(10,-11) 是 < 1，所以如果您将它转换为 long，它会变成 0 .

改变

Long gravitationalConstant = (long) (6.673*Math.pow(10,-11));

到

double gravitationalConstant = 6.673*Math.pow(10,-11);