I need finalizing this apex class to reset a password for the user and log the current user out of salesforce.  Here is my code any ideas I get this error message.

public class resetyourpassword {
  String user=userinfo.getuserId();
  system.resetPassword(user,true);
   PageReference demoPage = new pagereferenct('/secur/logout.jsp');
    demoPage.setRedirect(true);
}

I get an error unexpected token: ',' in line 3  where  system.resetPassword(user,true); id located

I need finalizing this apex class to reset a password for the user and log the current user out of salesforce.  Here is my code any ideas I get this error message.

public class resetyourpassword {
  String user=userinfo.getuserId();
  system.resetPassword(user,true);
   PageReference demoPage = new pagereferenct('/secur/logout.jsp');
    demoPage.setRedirect(true);
}

I get an error unexpected token: ',' in line 3  where  system.resetPassword(user,true); id located