Question

In Java

We define BigNumber a number consisting of 0<N<21 elements.It can be negative in which case it will have a minus sign in front. Without modifying main method complete the methods add, subtract and reverse. Hints: class java.math.BigInteger would be very useful. For reverse method number== new StringBuffer(number).reverse().toString(); can be used however when you reverse a negative number the negative sign should stay in front. Thanks.

public class MD3 {

public static void main(String[] args)
{
BigNumber BigNumber1 = new BigNumber(args[0]);
BigNumber BigNumber2 = new BigNumber(args[1]);

BigNumber1.add(BigNumber2);
BigNumber1.display();
BigNumber1.reverse();
BigNumber1.display();

BigNumber2.subtract(BigNumber1);
BigNumber2.display();
BigNumber2.reverse();
BigNumber2.display();
}

class BigNumber {

private String number;
  
BigNumber(String str) { number = str; }

public void add(BigNumber sk) { /* ... */ }

public void subtract(BigNumber sk) { /* ... */ }
  
public void reverse() { /* ... */ }

  

  
public void display() {System.out.println(number);}
}
}

Answer 1

SOURCE CODE:

*Please follow the comments to better understand the code.

**Please look at the Screenshot below and use this code to copy-paste.

***The code in the below screenshot is neatly indented for better understanding.


import java.math.BigInteger;
public class MD3 {

    public static void main(String[] args) {
        BigNumber BigNumber1 = new BigNumber(args[0]);
        BigNumber BigNumber2 = new BigNumber(args[1]);

        BigNumber1.add(BigNumber2);
        BigNumber1.display();
        BigNumber1.reverse();
        BigNumber1.display();

        BigNumber2.subtract(BigNumber1);
        BigNumber2.display();
        BigNumber2.reverse();
        BigNumber2.display();
    }
}
    class BigNumber {

        private String number;

        BigNumber(String str) { number = str; }

        public void add(BigNumber sk)
        {
            // convert number to BigInteger
            BigInteger number1 = new BigInteger(number);
            // add it
            number1 = number1.add(new BigInteger(sk.number));
            // store in number variable
            number = number1.toString();
        }

        public void subtract(BigNumber sk)
        {
            // convert number to BigInteger
            BigInteger number1 = new BigInteger(number);
            // subtract it
            number1 = number1.subtract(new BigInteger(sk.number));
            // store in number variable
            number = number1.toString();
        }

        public void reverse()
        {
            number= new StringBuffer(number).reverse().toString();
        }

       public void display() {System.out.println(number);}
    }

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CODE: