initial commit

c/isogram/src/isogram.c

@@ -0,0 +1,34 @@
+#include "isogram.h"
+#include <ctype.h>
+
+#define POS(c) (tolower(c)-'a')
+
+/* This does not work outside English world */
+bool is_isogram(const char phrase[])
+{
+    //int map['z'-'a'+1]={0};
+    int map[1000]={0};
+    const char *p=phrase;
+
+    if (!p)
+        return false;
+    for (; *p; ++p) {
+        if (*p==' ' || *p=='-')
+            continue;
+        if (!isalpha((unsigned char)*p) || (++map[POS((unsigned char)*p)])>1)
+            return false;
+    }
+    return true;
+}
+
+#ifdef UNIT_TEST
+#include <stdio.h>
+int main(int ac, char **av)
+{
+    int arg=1;
+
+    for (; arg<ac; ++arg) {
+        printf("isogram[%s]=%d\n", av[arg], is_isogram(av[arg]));
+    }
+}
+#endif