Source code in the mad programming language

            NORMAL MODE IS INTEGER

          R VERIFY DAMM CHECKSUM OF NUMBER
            INTERNAL FUNCTION(CKNUM)
            VECTOR VALUES DAMMIT = 
          0        0,3,1,7,5,9,8,6,4,2
          1     ,  7,0,9,2,1,5,4,8,6,3
          2     ,  4,2,0,6,8,7,1,3,5,9
          3     ,  1,7,5,0,9,8,3,4,2,6
          4     ,  6,1,2,3,0,4,5,9,7,8
          5     ,  3,6,7,4,2,0,9,5,8,1
          6     ,  5,8,6,9,7,2,0,1,3,4
          7     ,  8,9,4,5,3,6,2,0,1,7
          8     ,  9,4,3,8,6,1,7,2,0,5
          9     ,  2,5,8,1,4,3,6,7,9,0           
            DIMENSION DAMDGT(10)
            ENTRY TO DAMM.
            TMP=CKNUM
            THROUGH GETDGT, FOR NDGT=0, 1, TMP.E.0
            DAMDGT(NDGT) = TMP-TMP/10*10
GETDGT      TMP = TMP/10
            INTRM = 0
            THROUGH CKDGT, FOR NDGT=NDGT, -1, NDGT.L.0
CKDGT       INTRM = DAMMIT(INTRM*10 + DAMDGT(NDGT))
            FUNCTION RETURN INTRM.E.0
            END OF FUNCTION
            
          R TEST SOME NUMBERS
            THROUGH TEST, FOR VALUES OF N = 5724,5727,112946,112949
            WHENEVER DAMM.(N)
                PRINT FORMAT VALID,N
            OTHERWISE
                PRINT FORMAT INVAL,N
TEST        END OF CONDITIONAL
            
            VECTOR VALUES VALID = $I9,S1,5HVALID*$
            VECTOR VALUES INVAL = $I9,S1,7HINVALID*$
            END OF PROGRAM