Validate International Securities Identification Number: Difference between revisions

Content added Content deleted

Inline

@@ Line 2,702: / Line 2,702: @@
 =={{header|REXX}}==
-<syntaxhighlight lang="rexx">/*REXX program validates the  checksum digit for an  International Securities ID number.*/
+<syntaxhighlight lang="rexx"></syntaxhighlight>
-parse arg z                                      /*obtain optional  ISINs  from the C.L.*/
+/*REXX program validates International Securities ID numbers.                       */
+Parse Arg z                                  /*obtain ISINs  from the C.L.          */
-if z=''  then z= "US0378331005 US0373831005 U50378331005 US03378331005 AU0000XVGZA3" ,
-                 'AU0000VXGZA3 FR0000988040'     /* [↑]  use the default list of  ISINs.*/
+If z='' Then                                 /* [?]  use the default list of  ISINs */
+  z='US0378331005 US0373831005 U50378331005 US03378331005',
-                                                 /* [↓]  process  all  specified  ISINs.*/
+    'US037*331005',
-     do n=1  for words(z);  x=word(z, n);  y= x  /*obtain an  ISIN  from the  Z  list.  */
+    'XY037833100Z AU0000XVGZA3 AU0000VXGZA3 FR0000988040'
-     $=                                          /* [↓]  construct list of ISIN digits. */
+valid='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ' /*X must contain 0-->9 A-->Z           */
-        do k=1  for length(x);  _= substr(x,k,1) /*the ISIN may contain alphabetic chars*/
+Do n=1 To words(z)                           /* [?]  process  all  specified  ISINs.*/
-        p= pos(_, 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ)   /*X must contain A──►Z, 0──►9.*/
-        if p==0  then y=                                  /*trigger  "not"  valid below.*/
+  x=word(z,n)                                /*obtain an  ISIN  from the  Z  list.  */
+  p=verify(x,valid,'N')
-                 else $= $ || p-1                /*convert  X  string (base 36 ──► dec).*/
+  If p>0 Then msg='invalid character in position' p':' substr(x,p,1)
-        end   /*k*/                              /* [↑]  convert  alphabetic ──► digits.*/
+  Else Do
-     @=                                          /*placeholder for the "not" in message.*/
-     if length(y)\==12             then @= "not" /*see if the ISIN is exactly 12 chars. */
+    dd=''                                    /* [?]  construct list of ISIN digits. */
+    Do k=1 To length(x)
-     if \datatype( left(x,2),'U')  then @= "not" /* "   "  "    "  1st 2 chars cap. let.*/
-     if \datatype(right(x,1),'W')  then @= "not" /* "   "  "    "  last char not a digit*/
+      _=substr(x,k,1)                        /*the ISIN may contain alphabetic chars*/
-     if @==''  then  if \luhn($)   then @= "not" /* "   "  "    "  passed the Luhn test.*/
+       p=pos(_,valid)                        /*X contains 0-->9 A-->Z               */
-     say right(x, 30)   right(@, 5)   "valid"    /*display the   yea  or  nay   message.*/
+      dd=dd||p-1                             /*convert  X  string (base 36 --? dec).*/
+      End
-     end   /*n*/                                 /* [↑] 1st 3 IFs could've been combined*/
+    msg=''
-exit                                             /*stick a fork in it,  we're all done. */
+    Select
-/*──────────────────────────────────────────────────────────────────────────────────────*/
+      When length(x)\==12            Then msg='not exactly 12 chars'
-Luhn: procedure;  parse arg x;           $= 0    /*get credit card number;  zero $ sum. */
-      y= reverse( left(0, length(x) // 2)x)      /*add leading zero if needed, & reverse*/
+      When \datatype( left(x,2),'U') Then msg='not starting with 2 capital chars'
+      When \datatype(right(x,1),'W') Then msg='last character is not a digit'
-                            do j=1  to length(y)-1  by 2;    _= 2  *  substr(y, j+1, 1)
+      Otherwise
-                            $= $ + substr(y, j, 1)  +  left(_, 1)  +  substr(_, 2  , 1, 0)
-                            end   /*j*/          /* [↑]   sum the  odd and even  digits.*/
+         If \luhn(dd)                Then msg='does not pass the Luhn test'
+      End
-      return right($, 1)==0                      /*return "1" if number passed Luhn test*/</syntaxhighlight>
+    End
+  If msg='' Then
+    Say right(x,15) '    valid'              /* display the positive message.        */
+  Else
+    Say right(x,15) 'not valid:' msg         /* display the problem                  */
+  End   /*n*/
+Exit                                         /*stick a fork in it,  we're all done   */
+/*-----------------------------------------------------------------------------------*/
+luhn: Procedure
+  Parse Arg x                                /* get credit card number;              */
+  dsum=0                                     /* zero digit sum.                      */
+  y=reverse(left(0,length(x)//2)x)           /* add leading zero If needed & reverse */
+  Do j=1 To length(y)-1 By 2
+    _=2*substr(y,j+1,1)
+    dsum=dsum+substr(y,j,1)+left(_,1)+substr(_,2,1,0)
+    End
+  Return right(dsum,1)==0                    /* Return 1 if number passed Luhn test  */
 {{out|output|text=&nbsp; when using the default inputs:}}
 <pre>
-                  US0378331005       valid
+   US0378331005     valid
+   US0373831005 not valid: does not pass the Luhn test
-                  US0373831005   not valid
+   U50378331005 not valid: not starting with 2 capital chars
-                  U50378331005   not valid
+  US03378331005 not valid: not exactly 12 chars
-                 US03378331005   not valid
+   US037*331005 not valid: invalid character in position 6: *
-                  AU0000XVGZA3       valid
+   XY037833100Z not valid: last character is not a digit
-                  AU0000VXGZA3       valid
-                  FR0000988040       valid
+   AU0000XVGZA3     valid
+   AU0000VXGZA3     valid
+   FR0000988040     valid
 </pre>