java - 按元素对两个数组求和，携带 1 时出现问题

Question

所以我已经让这两个数组在不需要携带任何东西时正确添加。所以 a[0,1,1] + b[0,1,1] 会给我 c[0,0,2,2]，但如果我类似地做 a[0,9,9] + b[0, 9,9] 我只得到 c[0, 0, 8, 8]。 addBigInts 方法中的循环似乎没有按照我想象的方式工作。任何想法表示赞赏。

import java.util.*;

public class AddBigInts {

public static void main(String[] args) {
    Scanner console = new Scanner(System.in);
    //init firstNum array
    int[] firstNum = new int[getDigit()];
    System.out.println("First number:");
    //gets input to pop array
    firstNum = getInt(firstNum);
    //second array is same length
    int[] secondNum = new int[firstNum.length];
    System.out.println("Second number:");
    //pop second array
    secondNum = getInt(secondNum);
    System.out.println(Arrays.toString(firstNum));
    System.out.println(Arrays.toString(secondNum));
    addBigInts(firstNum, secondNum);
}

//creates array that is one place bigger than entered #
public static int getDigit (){
    Scanner console = new Scanner(System.in);
    System.out.print("How many digits? ");
    int arraySize = console.nextInt();
    return arraySize + 1;
}

//populates array
public static int[] getInt (int[] num){
    Scanner console = new Scanner(System.in);
    for (int i=num.length-1; i>0; i--){
        System.out.print("Digit " + i + ": ");
        num[i] = console.nextInt();
    }
    return num;

}

//adds both arrays by index into the sum array
public static int[] addBigInts (int[]numArray1, int[] numArray2){
    int count = Math.max(numArray1.length, numArray2.length);
    int[] sum = new int[count+1];
    //starting at numArray1 & 2 index, sums ints
    for (int i=count-1; i>=0; i--){
        //sum has to be +1 for numArray1 & 2 indexes
        sum[i+1] = numArray1[i] + numArray2[i];
        if (sum[i+1]>9){
            //this line below doesn't seem to execute
            sum[i]++;
            sum[i+1] = sum[i+1] - 10;
        }
        else;

        }
    System.out.println(Arrays.toString(sum));
    return sum;
    }
}

Answer 1

你有:

sum[i+1] = numArray1[i] + numArray2[i];

您需要:

sum[i+1] += numArray1[i] + numArray2[i];

通过赋值而不是相加，您将覆盖前一个数字中的进位 1。