Geneartion of max srlno +1 for a given table and a column

Question

Dear friends,
I am trying to write a function which will accept a table name and a column name (must be numeric) of that table, calculate the maximum value of the column name as under...
The funtion compiles fantastic but on execution it gives a lot of error. I admit to be a newbie writing dynamic sql, and hence needs help on that ....Below what I wrote...
create or replace function get_newsrl(TabNm user_tab_columns.TABLE_NAME%TYPE,ColNm user_tab_columns.COLUMN_NAME%TYPE) return number is
NewSrl number;
Begin
     NewSrl:=0;
     dbms_output.put_line(TabNm);
     dbms_output.put_line(ColNm);
     Begin
          Execute Immediate
          'Begin
          'select max(' || ColNm ||') into NewSrl from ' ||TabNm||' Using '||ColNm||','||TabNm||';';
          ||'end;';
     end;     
     NewSrl:=NewSrl+1;
Return NewSrl;
End;

Answer 1

SQL> create or replace function get_newsrl(TabNm Varchar2, ColNm Varchar2) return number is
  2  NewSrl number;
  3  Begin
  4  /*
  5  NewSrl:=0;
  6  dbms_output.put_line(TabNm);
  7  dbms_output.put_line(ColNm);
  8  */
  9  Execute Immediate
 10  'select max(' || ColNm ||') into NewSrl from ' ||TabNm;
 11  NewSrl:=NewSrl+1;
 12  Return NewSrl;
 13  Exception
 14  When OTHERS
 15  then return (- SQLCODE);
 16  End;
 17  /
Ôóíêöèÿ ñîçäàíà.
SQL> select get_newsrl('EMP', 'EMPNO') from dual;
GET_NEWSRL('EMP','EMPNO')
                      905
SQL>