Computer Science 101

with:  Erik Oosterwal

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Decimal to Hexadecimal


This routine wil convert an integer to hexadecimal.  It was originally written for a FORTRAN project I was workign on back in the late '80s that did not have that function built into the compiler.  The routine is pretty straight forward but is limited to Hex numbers of only 4 bytes.  It would be easy enough to allow larger hex strings by increasing the size of the string array (ARRY(4)) to 8, 16, or whatever size you need.  In order for the rountine to work properly, your language/compiler must truncate all non-whole number parts from integers when division results in a non-integer number.  MOD() returns the modulus, or remainder, of a division operation.



C     ****************************************** 
C 
C     ROUTINE TO CONVERT INTEGER VALUES TO HEX 
C 
C     WRITTEN BY:  ERIK PETER OOSTERWAL 
C     WRITTEN:  SEP 12, 1988 
C 
C     ****************************************** 
      SUBROUTINE DTOH(INUM,ARRY) 
C
      CHARACTER*1 ARRY(4),HEX(16) 
      INTEGER*2 INUM 
      DATA HEX/'0','1','2','3','4','5','6','7','8', 
     *     '9','A','B','C','D','E','F'/ 
C 
      DO 10 I = 4,1,-1 
           ARRY(I)=HEX(MOD(INUM,16)+1) 
   10      INUM = INUM/16 
C 
      RETURN 
      END



For a more generalized routine that can convert between any two numeric bases, see the Numeric Base Conversion article from the main Computer Science 101 page.




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All code and original algorithms are © Erik Oosterwal - 1987-2008
Computer Science 101

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