java格式（俄罗斯农民乘法）

Question

我想用这个方案来格式化俄罗斯农民乘法：问题是它不能处理更大的数字。

47 * 42
-------
23   84
11  168
 5  336
 2  672
 1 1344
=======
   1974

但当我的数字较大时，我的格式不匹配：

470 * 420
---------
235  840
117 1680
58 3360
29 6720
14 13440
 7 26880
 3 53760
 1 107520
=========
   197400

它应该是这样的：

470 * 420
----------
235    840
117   1680
 58   3360
 29   6720
 14  13440
  7  26880
  3  53760
  1 107520
==========
   197400

他们是一种为变量设置格式的方法吗？我目前已经用-和M硬编码了它？

这是我当前的代码：

public class Main {

public static void main (String[] args) {
    int num1=47;
    int num2=42;
    int product=0;
    String testNum1 = "";
    String testNum2 = "";


    if(num1%2!=0)
        product=product+num2;

    System.out.println(num1 + " * "+num2);
    int printLength = String.valueOf(num1).length() + String.valueOf(num2).length() + 3;
    for (int i = 0; i < printLength; i++){
        System.out.print('-');
    }
    System.out.println();
    while(num1!=1)
    {
        num1=num1/2;
        num2=num2*2;

        int x = String.valueOf(num1).length();

        if(num1%2!=0)
            product=product+num2;

        testNum1 = String.format("%2d", num1);
        testNum2 = String.format("%4d", num2);
        System.out.println(testNum1 + " " + testNum2);
    }
    for (int i = 0; i<printLength; i++){
        System.out.print("=");
    }
    System.out.println();
    System.out.print("   ");
    System.out.print(product);
}

}

Answer 1

-和M硬编码导致故障。有多种方法可以实现此模式。下面，你可以找到懒惰的人：P。

另外，你需要照顾-----

 //changes
List<String> list1 = new ArrayList<>();
List<String> list2 = new ArrayList<>();
int maxLength1 =0;
int maxLength2 =0;

while(num1!=1)
{
    num1=num1/2;
    num2=num2*2;

    int x = String.valueOf(num1).length();

    if(num1%2!=0)
        product=product+num2;


    String s1 = ""+num1;
    String s2 = ""+num2;
    list1.add(s1);
    list2.add(s2);
    maxLength1 = maxLength1>s1.length()?maxLength1:s1.length();  //getting the max length for both numbers
    maxLength2 = maxLength2>s2.length()?maxLength2:s2.length();

}


//main printing lines
for (int i = 0; i < list1.size(); i++) {

    //calculating and adding required spaces for both numbers.
    
    int firstSpace = maxLength1 - list1.get(i).length() ;
    String space1 = new String(new char[firstSpace]).replace('\0', ' ');
    
    int secondSpace = maxLength2 - list2.get(i).length() ;
    String space2 = new String(new char[secondSpace]).replace('\0', ' ');

    System.out.println(space1+list1.get(i)+" "+space2+list2.get(i));
}

//changed here for better visual representaion 
for (int i = 0; i<=(maxLength1+maxLength2) ; i++){
    System.out.print("=");
}
System.out.println();
System.out.print("   ");
System.out.print(product);

在线演示