plsql code for sum of 100 number

Declare

          a number;

          s1 number default 0;

Begin

          a:=1;

          loop

                    s1:=s1+a;

                    exit when (a=100);

                    a:=a+1;

          end loop;

          dbms_output.put_line('Sum between 1 to 100 is '||s1);

End;