Convert between different numbering systems ,binary, octal, decimal and hex

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CREATE OR REPLACE PACKAGE dbms_numsystem AS

   function bin2dec (binval in char  ) RETURN number;

   function dec2bin (N      in number) RETURN varchar2; 

   function oct2dec (octval in char  ) RETURN number;

   function dec2oct (N      in number) RETURN varchar2; 

   function hex2dec (hexval in char  ) RETURN number;

   function dec2hex (N      in number) RETURN varchar2; 

END dbms_numsystem;

/

show errors

CREATE OR REPLACE PACKAGE BODY dbms_numsystem AS

FUNCTION bin2dec (binval in char) RETURN number IS

  i                 number;

  digits            number;

  result            number := 0;

  current_digit     char(1);

  current_digit_dec number;

BEGIN

  digits := length(binval);

  for i in 1..digits loop

     current_digit := SUBSTR(binval, i, 1);

     current_digit_dec := to_number(current_digit);

     result := (result * 2) + current_digit_dec;

  end loop;

  return result;

END bin2dec;

FUNCTION dec2bin (N in number) RETURN varchar2 IS

  binval varchar2(64);

  N2     number := N;

BEGIN

  while ( N2 > 0 ) loop

     binval := mod(N2, 2) || binval;

     N2 := trunc( N2 / 2 );

  end loop;

  return binval;

END dec2bin;

FUNCTION oct2dec (octval in char) RETURN number IS

  i                 number;

  digits            number;

  result            number := 0;

  current_digit     char(1);

  current_digit_dec number;

BEGIN

  digits := length(octval);

  for i in 1..digits loop

     current_digit := SUBSTR(octval, i, 1);

     current_digit_dec := to_number(current_digit);

     result := (result * 8) + current_digit_dec;

  end loop;

  return result;

END oct2dec;

FUNCTION dec2oct (N in number) RETURN varchar2 IS

  octval varchar2(64);

  N2     number := N;

BEGIN

  while ( N2 > 0 ) loop

     octval := mod(N2, 8) || octval;

     N2 := trunc( N2 / 8 );

  end loop;

  return octval;

END dec2oct;

FUNCTION hex2dec (hexval in char) RETURN number IS

  i                 number;

  digits            number;

  result            number := 0;

  current_digit     char(1);

  current_digit_dec number;

BEGIN

  digits := length(hexval);

  for i in 1..digits loop

     current_digit := SUBSTR(hexval, i, 1);

     if current_digit in ('A','B','C','D','E','F') then

        current_digit_dec := ascii(current_digit) - ascii('A') + 10;

     else

        current_digit_dec := to_number(current_digit);

     end if;

     result := (result * 16) + current_digit_dec;

  end loop;

  return result;

END hex2dec;

FUNCTION dec2hex (N in number) RETURN varchar2 IS

  hexval varchar2(64);

  N2     number := N;

  digit  number;

  hexdigit  char;

BEGIN

  while ( N2 > 0 ) loop

     digit := mod(N2, 16);

     if digit > 9 then 

        hexdigit := chr(ascii('A') + digit - 10);

     else

        hexdigit := to_char(digit);

     end if;

     hexval := hexdigit || hexval;

     N2 := trunc( N2 / 16 );

  end loop;

  return hexval;

END dec2hex;

END dbms_numsystem;

/

show errors

-- Examples:

select dbms_numsystem.dec2bin(22)      from dual;

select dbms_numsystem.bin2dec('10110') from dual;

select dbms_numsystem.dec2oct(44978)   from dual;

select dbms_numsystem.oct2dec(127662)  from dual;

select dbms_numsystem.dec2hex(44978)   from dual;

select dbms_numsystem.hex2dec('AFB2')  from dual;