处理多个前导零

Question

我正在写一个计算校验和的程序，但需要删除前面的所有前导零。我知道如何只删除一个，但我如何删除它们全部？

这是我到目前为止所知道的：

 Scanner scan = new Scanner(System.in);
  System.out.print("Enter the first 9 digits of an ISBN as an integer: ");
  ISBN = scan.nextInt();


  /******************************************************************************
  *                           Processing Section                              *
  ******************************************************************************/
  processingISBN = ISBN;     
  sum = 0;
  for (int i = 2; i <= 10; i++) 
  {
     digit = processingISBN % 10;  // digit at the end
     sum = sum + i * digit;
     processingISBN = processingISBN / 10;
  }
  firstDigit = ISBN / 100000000; // grab first digit (in case of zero)

  /******************************************************************************
  *                              Outputs Section                                *
  ******************************************************************************/

   // print out check sum number, use X for 10



  if (firstDigit == 0)
  {
     System.out.print("The ISBN-10 number is 0" + ISBN);
  }
  if (firstDigit != 0)
  {
     System.out.print("The ISBN-10 number is " + ISBN);
  }

  if(sum % 11 == 1) //checks for checksum=10 
  {
     System.out.print("X");
  }
  else if (sum % 11 == 0) 
  {
     System.out.print("0");
  }
  else                    
  {
     System.out.print(11 - (sum % 11)); 
  }

值得一提的是: ISBN必须作为整数处理，而不是字符串。

Answer 1

尝试这样做，将ISBN构建为字符串，然后运行以下命令：

String yourInputAsString = "0000002514";
int yourInputAsInt;
Pattern p = Pattern.compile("^\\d+$");
Matcher m = p.matcher(yourInputAsString);

if(m.matches()){
    yourInputAsInt = Integer.valueOf(yourInputAsString.replaceAll("^0+", ""));
    System.out.println("As String: " + yourInputAsString.replaceAll("^0+", ""));
    System.out.println("As Int: " + yourInputAsInt);

        //do check

} else {
    System.out.println(yourInputAsString);
}

输出：

As字符串: 2514

As接口: 2514