Data commit

Task/Validate-International-Securities-Identification-Number/C/validate-international-securities-identification-number.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+
+int check_isin(char *a) {
+    int i, j, k, v, s[24];
+
+    j = 0;
+    for(i = 0; i < 12; i++) {
+        k = a[i];
+        if(k >= '0' && k <= '9') {
+            if(i < 2) return 0;
+            s[j++] = k - '0';
+        } else if(k >= 'A' && k <= 'Z') {
+            if(i == 11) return 0;
+            k -= 'A' - 10;
+            s[j++] = k / 10;
+            s[j++] = k % 10;
+        } else {
+            return 0;
+        }
+    }
+
+    if(a[i]) return 0;
+
+    v = 0;
+    for(i = j - 2; i >= 0; i -= 2) {
+        k = 2 * s[i];
+        v += k > 9 ? k - 9 : k;
+    }
+
+    for(i = j - 1; i >= 0; i -= 2) {
+        v += s[i];
+    }
+
+    return v % 10 == 0;
+}
+
+int main() {
+    char *test[7] = {"US0378331005", "US0373831005", "U50378331005",
+                     "US03378331005", "AU0000XVGZA3", "AU0000VXGZA3",
+                     "FR0000988040"};
+    int i;
+    for(i = 0; i < 7; i++) printf("%c%c", check_isin(test[i]) ? 'T' : 'F', i == 6 ? '\n' : ' ');
+    return 0;
+}
+
+/* will print: T F F F T T T */