java - how to use the a string value for arithmetic equations? -

i’m trying write method computes value of arithmetic expression. method takes 2 int parameters value1 , value2 , string parameter operator. i’m suppose throw illegalargumentexception if operator isn’t *, /, -, or + or if / followed value2 of 0.

how string value work in arithmetic expression? far code have:

  public static int compute(int value1, string operator, int value2)   {   if ((!operator.equals("+")) || (!operator.equals("*")) ||       (!operator.equals("-")) || (!operator.equals("/")))      {         throw new illegalargumentexception("invalid operator");      }   if ((operator.equals("/")) && (value2 == 0))      {         throw new illegalargumentexception("divide 0 error");      }      int result;       return result = (value1 + operator + value2);   } 

i think best option switch case, see example code:

int result;  switch (operator) {     case "+":               result = value1 + value2;               break;     case "-":               result = value1 - value2;               break;     case "*":               result = value1 * value2;               break;     case "/":               //check if value2 0 handle divide 0 exception               if(value2 != 0)                   result = value1 / value2;                else                   system.out.println("division not possible");                break;     default:              throw new illegalargumentexception("invalid operator: " + operator);  }  return result; 

and in case default case replace first if check , able remove it.