title: How can I compute a difference between two strings?
body: <p>I want to create a function in Delphi that computes different levels of two strings. If two strings are equal (ignoring case), then it should return 0, but if they are not equal, it should return the number of different characters. This function can be very useful for checking spelling.</p>
  
  <pre><code>function GetDiffStringLevel(S1,S2:string):Integer;
  begin
    if SameText(S1,S2) then Exit(0);
    // i want get different chars count
  end
  </code></pre>
  
  <p>samples code:</p>
  
  <pre><code>Diff:=GetDiffStringLevel('Hello','Hello');// Diff:=0;
  Diff:=GetDiffStringLevel('Hello','2Hello');// Diff:=1;
  Diff:=GetDiffStringLevel('Hello','H2ello');// Diff:=1;
  Diff:=GetDiffStringLevel('Hello','Hello W');// Diff:=2;
  Diff:=GetDiffStringLevel('Hello','World');// Diff:=6; or 5
  </code></pre>