title: case class product iterator to make string
body: <p>I want to make a string representation of case class</p>
  
  <pre><code> case class Person(s:Student)
    case class Student(name:String,value:String){
      def toMyString(flag:Boolean):String= if(flag)s"${name} =${value}" else s"Hello${name}+${value}"
    }
  
    Person(Student("abc","def")).productIterator
  </code></pre>
  
  <p>I want to call <code>toMyString</code> from <code>productIterator</code>.</p>
  
  <p>My actual use case has many elements in case class .</p>