ISBN13 check digit: Difference between revisions

Content added Content deleted

Inline

@@ Line 1,279: / Line 1,279: @@
 =={{header|EasyLang}}==
 <syntaxhighlight lang="text">
-proc ISBN13check ISBN$ . valid .
+func ISBN13check isbn$ .
-   for i = 1 to len ISBN$
+   for c$ in strchars isbn$
-      currentChar$ = substr ISBN$ i 1
+      if c$ <> "-"
-      if currentChar$ <> "-"
+         ndigs += 1
-         digitCounter += 1
       .
-      currentDigit = number currentChar$
+      dig = number c$
-      if digitCounter mod 2 = 0
+      if ndigs mod 2 = 0
-         currentDigit *= 3
+         dig *= 3
       .
-      sum += currentDigit
+      sum += dig
    .
-   if sum mod 10 = 0
+   if sum mod 10 <> 0
-      valid = 1
+      return 0
-   else
-      valid = 0
    .
+   return 1
 .
-ISBNcodes$[] = [ "978-0596528126" "978-0596528120" "978-1788399081" "978-1788399083" ]
+codes$[] = [ "978-0596528126" "978-0596528120" "978-1788399081" "978-1788399083" ]
-for ISBN$ in ISBNcodes$[]
+for code$ in codes$[]
-   call ISBN13check ISBN$ valid
+   if ISBN13check code$ = 1
+      print code$ & " is a valid ISBN"
-   if valid = 1
-      print ISBN$ & " is a valid ISBN"
    else
-      print ISBN$ & " is not a valid ISBN"
+      print code$ & " is not a valid ISBN"
    .
 .