java - 如何正确对齐和格式化不同的字符串长度

Question

如何将 string.format 和 printf 应用于我的输出，以便我可以根据我的作业要求对其进行对齐？

我的方法有 3 个输入，其中 2 个是保存两个数字的 char 数组，以及一个保存它们总和的 int 数组。

我已经格式化了数字和总和，使其成为一个散布有适当逗号的字符串。我现在的任务是对齐这些输出，以便它们始终正确对齐。问题是我不能只将列宽设置为特定数字，因为输入会因用户输入而变化。

例如:用户输入数字1和数字2(最多30位数字)，程序将数字相加并返回总数。

这是我的代码和当前输出:

import java.util.Scanner;
import java.util.Arrays;
public class Lab8{
    public static void main(String[] args){
        char[] num1 = {'9','2','3','8','7','4','8','6','7','2','9'};
        char[] num2 = {'3','9','9','8','3','9','2','8','3','4','9','4','5','8'};
        //getNumber("First Number: ");
        //getNumber("Second Number: ");
        //printArray(num1);
        //System.out.println();
        //printArray(num2);
        int[] finalTotal = sumArrays(num1,num2);
        //sumArrays(num1, num2);

        printOutput(num1, num2, finalTotal);

    }
    //-------- 
   /** Read a line of message from keyboard and return it as an array of char
      @return: Array of characters 
     */
    public static char[] getNumber(String msg){
        String myMessage;
        System.out.print(msg);
        Scanner input = new Scanner(System.in);
        myMessage = input.nextLine();// Read a line of message
        return myMessage.toCharArray();
   }   


   public static int[] sumArrays(char[] num1, char[] num2){

        int sum= 0, carry = 0, size = 0, min = 0;

        if(num1.length > num2.length){
            size = num1.length + 1;
            min = num2.length;
        }else{
            size = num2.length + 1;
            min = num1.length;
        }   

        int[] sumArray = new int[size];


        int i = num1.length-1;
        int j = num2.length-1;
        int k = size-1;

        while(i >= 0 && j >=0){

           sum = Character.getNumericValue(num1[i]) + Character.getNumericValue(num2[j]) + carry;
           i--;
           j--;
           sumArray[k] = sum % 10;
           sum = sum / 10;
           carry = sum % 10;
           k--;

       }   

        while(i >= 0){

            sum = Character.getNumericValue(num1[i]) + carry;
            sumArray[k] = sum % 10;
            sum = sum / 10;
            carry = sum % 10;
            i--;
            k--;

        }

        while( j >= 0){

            sum = Character.getNumericValue(num2[j]) + carry;
            sumArray[k] = sum % 10;
            sum = sum / 10;
            carry = sum % 10;
            j--;
            k--;

        }   

        sumArray[k] = carry;

        int[] finalSum = new int[sumArray.length-1];

        finalSum = printArray(sumArray);

        return finalSum;

   }  

      public static void printOutput(char[] num1, char[] num2, int[] sum){

        char[] largest = new char[1];
        char[] smallest = new char[1];
        char[] tmp = new char[1];

        if(num2.length > num1.length){
            largest = num2;
            smallest = num1;
        }else{
            largest = num1;
            smallest = num2;
        }     

        String number1 = formatString(largest);
        String number2 = formatString(smallest);
        String total = formatString(sum);


        System.out.printf("%s%n", number1 + " +");

        for(int i = 0; i < (number1.length() -  number2.length()); i++){
            System.out.print(" ");
        }   
        System.out.printf("%s%n%s%n%s", number2, totalLine(sum),total);

   }  


   public static String formatString(char[] num){

       String formattedString = "";

       for(int i = 0; i < num.length; i++){

           if(i == 0){
                formattedString = num[num.length-1-i] + formattedString;
                continue;
            }

            if(i % 3 == 0){
                formattedString = "," + formattedString;
            }

            formattedString = num[num.length-1-i] + formattedString;
       }   

       return formattedString;

   }  


    public static String totalLine(int[] num){

        String totalLine = "";

        for(int i = 0; i < num.length; i++){

            totalLine = "- " + totalLine;

        }   

        return totalLine;

    }   


    public static String formatString(int[] num){

        String formattedString = "";

       for(int i = 0; i < num.length; i++){

           if(i == 0){
                formattedString = num[num.length-1-i] + formattedString;
                continue;
            }

            if(i % 3 == 0){
                formattedString = "," + formattedString;
            }

            formattedString = num[num.length-1-i] + formattedString;
       }   

       return formattedString;

   }  


   public static int[] printArray(int[] arr){
        int[] sum = new int[arr.length-1];
        if(arr[0] == 0){
           for(int i = 1; i < arr.length; i++){
                sum[i-1] = arr[i];
            }
        }else{
            for(int i = 0; i < arr.length; i++){
                sum[i] = arr[i];
            }   
        }   
        return sum;
    }

}

输出(错误)

39,983,928,349,458 +
92,387,486,729
- - - - - - - - - - - - - - 
40,076,315,836,187

输出(正确的方式)

       39,983,928,349,458 + 
           92,387,486,729
     --------------------
       40,076,315,836,187

如您所见，我的格式有缺陷。我完全不确定如何正确格式化此输出，以便即使数值不同，每次也能正确显示。它的格式应该是较大的数字位于较小的数字之上，然后是总行，后面是总和。

Answer 1

因此，在阅读了更多内容后，我意识到我想要实现的目标并不一定需要字符串格式或 printf 语句。我最终像前面的评论和上面建议的答案一样，只是用多个打印语句格式化输出。这绝对不是最漂亮的代码，但它给了我我想要的确切输出。

这是实现这一目的的代码:

System.out.println("  " + number1 + " +");
for(int i = 0; i < (number1.length() - number2.length()); i++){
    System.out.print(" ");
}
System.out.println("  " + number2);
System.out.print(" ");
for(int j = 0; j < ((number1.length() - number2.length())+ number2.length()+1); j++){
    System.out.print("-");
}
System.out.println();
System.out.print("  " + total);