Why isn't the divide() function working in Java BigInteger?

Question

I'm attempting to divide the variable 'c' by 2(stored in 'd'). For some reason that doesn't happen. I'm passing 10 and 2 for input right now.

import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.BigInteger;

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
    Scanner sc = new Scanner(System.in); 
    BigInteger a = new BigInteger(sc.next()); 
    BigInteger b = sc.nextBigInteger();
    BigInteger d = new BigInteger("2"); 
    System.out.println(d);

    BigInteger c = a.subtract(b); 
    c.divide(d);
    System.out.println(c);
    a.subtract(c); 

    System.out.println(a); 
    System.out.println(c);
    }
} 

Any help would be appreciated. Thanks in advance!

Answer 1

You are forgetting that BigInteger is immutable. That means that a.divide(b) does not change a it returns the result of the calculation .

You need a = a.divide(b) or similar.

    BigInteger a = new BigInteger(sc.next());
    BigInteger b = sc.nextBigInteger();
    BigInteger d = new BigInteger("2");
    System.out.println(d);

    BigInteger c = a.subtract(b);
    // HERE!
    c = c.divide(d);
    System.out.println(c);
    // HERE!
    a = a.subtract(c);

    System.out.println(a);
    System.out.println(c);

Answer 2

BigInteger is immutable. You get the result of c.divide(d); as the return value, which you throw away in your code.