C solution for week 111, part 2

2 files changed, 61 insertions, 0 deletions

diff --git a/challenge-111/abigail/README.md b/challenge-111/abigail/README.md
index 53215ce77d..3f7fc99b5f 100644
--- a/challenge-111/abigail/README.md
+++ b/challenge-111/abigail/README.md
@@ -51,6 +51,7 @@ to standard output. In case of ties, we print the first one found.
 
 ### Solutions
 * [GNU AWK](awk/ch-2.gawk)
+* [C](c/ch-2.c)
 * [Perl](perl/ch-2.pl)
 
 ### Blog
diff --git a/challenge-111/abigail/c/ch-2.c b/challenge-111/abigail/c/ch-2.c
new file mode 100644
index 0000000000..a677e4cad6
--- /dev/null
+++ b/challenge-111/abigail/c/ch-2.c
@@ -0,0 +1,60 @@
+# include <stdlib.h>
+# include <stdio.h>
+# include <string.h>
+# include <stdbool.h>
+# include <ctype.h>
+
+/*
+ * See ../README.md
+ */
+
+/*
+ * Run as: cc -o ch-2.o ch-2.c; ./ch-2.o < input-file
+ */
+
+int main (void) {
+    char *  line         = NULL;
+    size_t  len          =    0;
+    char *  longest      = NULL;
+    size_t  longest_size =    0;
+
+    while (getline (&line, &len, stdin) != -1) {
+        /*
+         * First check whether the word has its characters
+         * in lexical order.
+         */
+        size_t i      = 0;
+        bool in_order = 1;
+        while (line [i] != '\n') {
+            if ((i && tolower (line [i]) < tolower (line [i - 1])) ||
+                !isalpha (line [i])) {
+                in_order = false;
+                break;
+            }
+            i ++;
+        }
+
+        /*
+         * If we have a word with its characters in lexical order, and
+         * it's longer than the longest word found, keep the word.
+         */
+        if (in_order && i > longest_size) {
+            longest_size = i;
+            if ((longest = (char *) realloc (longest, (i + 1) * sizeof (char)))
+                 == NULL) {
+                perror ("Realloc failed");
+                exit (1);
+            }
+            for (size_t j = 0; j <= i; j ++) {  /* Copies the newline as well */
+                longest [j] = line [j];
+            }
+            longest [i + 1] = '\0';
+        }
+    }
+    printf ("%s", longest);
+
+    free (line);
+    free (longest);
+
+    return (0);
+}