alter database backup controlfile to ['filename' | trace]

This command comes in two versions. One backs up the control file in a binary format while the other backs it up in a human readable form. It is required if the database is running inarchive log mode and a structural change was made to the database.
Backing it up in a binary format:
alter database backup controlfile to '/some/arbitrary/path';
alter database backup controlfile to '/some/arbitrary/path' reuse;
Backing it up in a human readable format:
alter database backup controlfile to trace;
alter database backup controlfile to trace as '/some/arbitrary/path';
alter database backup controlfile to trace as '/some/arbitrary/path' reuse;

2. remove the control files(control01.ctl,control02.ctl,control03.ctl) from the location C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\ for testing purpose to re-create it.

3. run the script below to recreate a lost control files

CREATE CONTROLFILE REUSE DATABASE "assad" RESETLOGS FORCE LOGGING ARCHIVELOG
  MAXLOGFILES 16
  MAXLOGMEMBERS 3
  MAXDATAFILES 100
  MAXINSTANCES 8
  MAXLOGHISTORY 292
LOGFILE
GROUP 1 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\redo01.log'  SIZE 5M,
GROUP 2 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\redo02.log'  SIZE 5M,
GROUP 3 'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\redo03.log'  SIZE 5M
-- STANDBY LOGFILE
DATAFILE
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\SYSTEM01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\UNDOTBS01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\SYSAUX01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\USERS01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\EXAMPLE01.DBF',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\EMP',
'C:\ORACLE\PRODUCT\10.2.0\ORADATA\ASSAD\EMPDATA'
CHARACTER SET WE8ISO8859P1
;
Control file created.

SQL> alter database open resetlogs;

Database altered.

and this is the end of your test.