How to implement Body Mass Index (BMI)in Java

Question

My problem is how can I implement without the Scanner method and with Math.round and Math.pow?

Here is my code:

import java.util.Scanner;
    public class BMI{
       public static void main(String args[]) {
          Scanner sc = new Scanner(System.in);
          System.out.print("Input weight in kilogram: ");
          double weight = sc.nextDouble();
          System.out.print("\nInput height in meters: ");
          double height = sc.nextDouble();
          double BMI = weight / (height * height);
          System.out.print("\nThe Body Mass Index (BMI) is " + BMI + " kg/m2");
       }
    }

My another idea was It is only for a certain value. In my case with a weight of 75.0 and size 178.0

public static void main(String args[]) {

    double weight = 75.0;
    double height = 178.0;

    double BMI = weight / (height * height);
    System.out.print("\nThe Body Mass Index (BMI) is " + BMI + " kg/m2");
 }

Answer 1

It's up to developer to choose how to initialize parameters.
If don't want to use scanner the simple way is just add directly.
Initialize can also come from various data-sources: database, file (xml,text), web-service, etc.
For school purpose maybe you could try to build a BMI class and use constructor to pass whatever parameters may want.
Advantage to have a constructor with parameters is that you can build various BMI instances with different result(based on params), not just have only 1 result in for all the class-instances (due to the fact the input is the same).

eg:

public class BMI 
{
    double BMI;
    public BMI(double weight,double height )
    {
        this.BMI = weight / (height * height);
    }
    
    public String toString()
    {
        return "\nThe Body Mass Index (BMI) is " + this.BMI + " kg/m2";
    }
    
    public static void main(String args[])
    {
        BMI test1 = new BMI(100,1.90);
        BMI test2 = new BMI(68.77,1.60);
        System.out.println(test1);
        System.out.println(test2);
    }
}

Output:

The Body Mass Index (BMI) is 27.70083102493075 kg/m2
The Body Mass Index (BMI) is 26.863281249999993 kg/m2