[Have code] Need Help!!

Question

class JavaTest{
     public static void main(String[] arg){
          String str = "123 + 456";
          String arr[] = str.split(" ");
          arr[0] // 123
arr[1] // +
arr[2] // 456
I want to output the ans which is 123+456 (579)
How??
if str = 45 - 45
i would like it output 0

Answer 1

public class QuickTest
     public static void main(String[] arg)
          String str = "123 + 456";
          String arr[] = str.split(" ");
          char operand = arr[1].charAt(0);
          int leftSide = Integer.parseInt(arr[0]);
          int rightSide = Integer.parseInt(arr[2]);
          int result = 0;
          switch (operand)
               case '+':
                    result = leftSide + rightSide;
                    break;
               case '-':
                    result = leftSide - rightSide;
                    break;
          System.out.println(result);
}This code works, to an extent. You might want to add more 'case' statements to allow for * and /. Also, at the moment, if you put the initial string in as "123 * 34", the program would compile and run, and give the output 0. This is obviously wrong, so you might want to write code that checks for unexpected events.
Just something to keep you going.......!