title: Error in building simple calculator logic using when expression in Kotlin
body: <p>This is my code:</p>
  <pre><code>fun main() {
      // write your code here
      val firstNumber:Long = readLine()!!.toLong()
      val secondNumber:Long = readLine()!!.toLong()
      val operator = readLine()!!
      when (operator) {
          &quot;+&quot; -&gt; println(firstNumber + secondNumber)
          &quot;-&quot; -&gt; println(firstNumber - secondNumber)
          &quot;/&quot; -&gt; if (secondNumber == 0.toLong()) println(&quot;Division by 0!&quot;) else println(firstNumber / secondNumber)
          &quot;*&quot; -&gt; println(firstNumber * secondNumber)
  
          else -&gt; println(&quot;Unknown operator&quot;)
      }
  }
  </code></pre>
  <p>I think I am doing everything right but still having an error as shown in image.<a href="https://i.stack.imgur.com/tECGe.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tECGe.png" alt="enter image description here" /></a></p>
  <p>Please help me to find where I am wrong.</p>