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         I N T E R P R E T E D    B A S I C    R E V I S I T E D     4. 
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     I submit these two mini-programs as evidence as to how elegant BASIC can 
     be.  FACTORAL.BAS asks BASIC to do a little recursion. Enter any integer 
     from 1 to 18 and its factorial is returned in decimal form.  
                   
                  10  CLS: DEFDBL N: INPUT N: IF N>18 OR N<>INT(N) THEN 10  
                  20  FOR J=N-1 TO 1 STEP -1: N=J*N NEXT J: PRINT N  
                    
      
     CHECKSUM.BAS  scans  a  given  12-digit  number to see if the sum of its 
     digits is divisible by seven. If the number is not so divisible or if it 
     is not an integer or if it does not have 12 digits, it is rejected.  
  
                  10  CLS: INPUT A$: FOR J=1 TO LEN(A$): B$=MID$(A$,J,1)  
                  20  B=VAL(B$): C=C+B: NEXT J  
                  30  IF C=0 OR C MOD7<>0 OR LEN(A$)<>12 THEN 50  
                  40  PRINT "OK": GOTO 60  
                  50  PRINT "REJECTED"  
                  60  END  
