编写程序实现两个超长正整数（每个最长80位数字）的减法运算。用java编写

以下是 Java 代码实现：

import java.util.Scanner;

public class LongIntSubtraction {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter the first number: ");
        String num1 = sc.nextLine();
        System.out.print("Enter the second number: ");
        String num2 = sc.nextLine();

        int[] result = subtract(num1, num2);

        System.out.print("Result: ");
        for (int i = result.length - 1; i >= 0; i--) {
            System.out.print(result[i]);
        }
    }

    public static int[] subtract(String num1, String num2) {
        int[] result = new int[80];

        int index = 79;
        int carry = 0;

        for (int i = num1.length() - 1, j = num2.length() - 1; i >= 0 || j >= 0; i--, j--) {
            int n1 = (i >= 0) ? num1.charAt(i) - '0' : 0;
            int n2 = (j >= 0) ? num2.charAt(j) - '0' : 0;

            int diff = n1 - n2 - carry;

            if (diff < 0) {
                diff += 10;
                carry = 1;
            } else {
                carry = 0;
            }

            result[index--] = diff;
        }

        while (index >= 0 && result[index] == 0) {
            index--;
        }

        if (index == -1) {
            return new int[] { 0 };
        }

        int[] res = new int[index + 1];

        for (int i = 0; i <= index; i++) {
            res[i] = result[i];
        }

        return res;
    }
}

该代码使用数组实现超长正整数的减法运算，支持任意长度的数字。它从最低位开始相减，如果结果小于0，则借位1，否则不借位。最后，需要去掉结果数组中前导的0，并且如果结果为0，则返回一个长度为1的数组。