Question

please help me

I need two methods that add and subtract two very large numbers in java created in a class called number and it runs on the demo below class below.

Please don't use parseInt or BigIntger, they are not allowed.

Thank you so much

public class demoClass {

public static void main(String[] args) {

number num1; //number is class that we need to create to the add and subtract methods

num1 = new number("11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111");

number num2; //number is class that we need to create to the add and subtract methods

num2 = new number("22222222222222222222222222222222222222222222222222222222222222222222222222222222");

number sum = num1.add(num2);

number minus = num1.subtract(num2);

}

}

Answer 1

public class number {

        private int[] n;

        public number() {
                n = new int[1];
        }

        public String trimZeroes(String s) {
                return s;
        }

        public number(String s) {
                while (s.startsWith("0")) {
                        s = s.substring(1);
                }
                n = new int[s.length()];

                for (int i = 0; i < n.length; ++i) {
                        n[n.length - i - 1] = s.charAt(i) - '0';
                }
        }

        public number(long n) {
                this.n = new int[String.valueOf(n).length()];
                int count = 0;

                while (n > 0) {
                        this.n[count++] = (int) (n % 10);
                        n = n / 10;
                }
        }

        public number add(number o) {
                int carry = 0;
                int max = n.length > o.n.length ? n.length : o.n.length;
                int[] result = new int[max + 1];

                for (int i = 0; i <= max; ++i) {

                        int top = i < n.length ? n[i] : 0;
                        int bot = i < o.n.length ? o.n[i] : 0;

                        result[i] = (top + bot + carry) % 10;
                        carry = (top + bot + carry) / 10;
                }

                return new number(join(result));
        }

        // Assuming Calling BigInteger is greater in value
        public number subtract(number o) {
                int carry = 0;
                int max = n.length > o.n.length ? n.length : o.n.length;
                int[] result = new int[max + 1];

                for (int i = 0; i <= max; ++i) {

                        int top = i < n.length ? n[i] : 0;

                        // remove carry
                        top = top - carry;
                        // reset carry
                        carry = 0;

                        int bot = i < o.n.length ? o.n[i] : 0;

                        // check if we need to take a carry
                        if (top < bot) {
                                top = top + 10;
                                carry = 1;
                        }

                        result[i] = (top - bot);
                }

                return new number(join(result));
        }

        private String join(int[] nums) {
                String result = "";
                for (int i = nums.length - 1; i >= 0; --i) {
                        result += nums[i];
                }
                return result;
        }

        public String toString() {
                String s = "";
                for (int i : n) {
                        s = i + s;
                }
                return s;
        }

        public static void main(String[] args) {
                number num1; // number is class that we need to create to the add and subtract methods

                num1 = new number(
                                "11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111");

                number num2; // number is class that we need to create to the add and subtract methods

                num2 = new number("22222222222222222222222222222222222222222222222222222222222222222222222222222222");

                number sum = num1.add(num2);
                number minus = num1.subtract(num2);
                
                System.out.println(sum);
                System.out.println(minus);
        }

}

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