title: Indexof () argument type
body: <p>Example1: indexOf(int ch)  //ex:   s.indexOf('y');
  Example2:replace(char original, char replacement) </p>
  
  <p>In both the examples the argument is expecting type char. Though it's mentioned as int in example 1 ,at the end it is expecting argument with single quote which is character. It could have directly been like char ch. Why there exists int type?  They could have specified it same like example 2.</p>
  
  <p>Is there any internal reason for this.why the syntax differs in some cases. There must a reason to do so.  Plz explain me this... </p>