Update network.c

Author: dreamer-coding

code/logic/network.c

@@ -15,6 +15,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <sys/time.h>    // For struct timeval
 #include <unistd.h>      // For close on POSIX systems