Update

mark_dead_links.c

@@ -0,0 +1,52 @@
+#include <stdio.h>
+
+int main(void)
+{
+  int c, state = 0, filenameLen = 0;
+  char filename[256];
+
+  while ((c = getchar()) != EOF)
+  {
+    putchar(c);
+
+    switch (state)
+    {
+      case 0: if (c == '<') state = 1; break;      
+      case 1: state = c == 'a' ? 2 : 0; break;      
+      case 2: state = c == ' ' ? 3 : 0; break;      
+      case 3: state = c == 'h' ? 4 : 0; break;      
+      case 4: state = c == 'r' ? 5 : 0; break;      
+      case 5: state = c == 'e' ? 6 : 0; break;      
+      case 6: state = c == 'f' ? 7 : 0; break;      
+      case 7: state = c == '=' ? 8 : 0; break;      
+      case 8: state = c == '"' ? 9 : 0; break;      
+      case 9:
+        if (c == '"')
+        {
+          filename[filenameLen] = 0;
+
+          FILE *f = fopen(filename,"r");
+
+          if (!f)
+            printf(" class=\"dead\"");
+          else
+            fclose(f);
+
+          filenameLen = 0;
+          state = 0;
+        }
+        else if (filenameLen < 128)
+        {
+          filename[filenameLen] = c;
+          filenameLen++;
+        }
+
+        break;
+
+      default: break;
+    }
+
+  }
+
+  return 0;
+}

style.css

@@ -13,3 +13,8 @@ table td, th
   border: 1px solid black;
   padding: 4px;
 }
+
+.dead
+{
+  color: red;
+}