title: Illegal start of expression java operators
body: <p>I am trying to write a program that evaluates a postfix expression.  My idea is to stack the operands and then pop out the necessary operands when an operator occurs.  I am trying to check if the input is an operand is an operator or operand, but the only "if" statement of this beginning code is returning "error: illegal start of expression" at the first instance of ||.  Am I missing escape characters or something else?  Thanks in advance.</p>
  
  <pre><code>public class Evaluate{
  char input[] = new char[50];
  Stack operands = new Stack();
  
      public string Evaulate(string input){
          for (int k = 0; input[k] != null; k++){
              char symb = input.charAt[k];
              if (symb != (+ || - || * || / || $){
                  operands.push(symb);
              }
          }
      }
  }
  </code></pre>