返回所有整数的和

Question

Program should return sum of all the numbers in a string.

public static void main(String[] args) {
    String data = "1a2b-3c";
    data=data.replaceAll("[\\D]+"," ");
    String[] numbers=data.split(" ");
    int sum = 0;
    for(int i=0;i<numbers.length;i++){
        try{
            sum+=Integer.parseInt(numbers[i]);
        }
        catch( Exception e ) {
          e.printStackTrace();
        }
    }
    System.out.println("The sum is:"+sum);

}

So for the above input, it should return sum as 0 ==> (1+2 - 3)

But my above code returns 6. What is the right regex for this?

Answer 1

Here's how you should do it

String data = "1a2b-3c";
int sum=0;
Pattern p = Pattern.compile("-?\\d+");
Matcher m = p.matcher(data);
while (m.find()) {
  sum+=Integer.parseInt(m.group());
}

Answer 2

A simple way would be to do this.

 if(numbers[i - 1].equals('-')){
           sum-=Integer.parseInt(numbers[i]);
 } else 
   sum+=Integer.parseInt(numbers[i]);

Answer 3

Use the split tool on your String, splitting every symbol individually into an array , then just add the numbers with parseInt and you're done. No need for a pattern here I think.