enforce mode selection, fix indentation, add usage

main.cc

@@ -60,16 +60,33 @@ struct waitClientArgs {
 		    // struct to keep track of
 };
 
+void usage(char *progname);
+
 int
 main(int argc, char *argv[])
 {
-	if (argc > 1 && (!strncmp(argv[1], "client", 6))) {
+	/*
+	 * userInput: character buffer for the user's next message
+	 * exit: set to true when infinite loop is to end
+	 * modeless: check whether a modeless exit was accidental
+	 */
+	char *userInput = new char[1024];
+	bool exit = false;
+	bool modeless = false;
+
+	if (argc > 1) {
+		if (!strncmp(argv[1], "client", 6)) {
 			logFileName = "client.txt";
 			mode = CLIENT_MODE;
-	} else {
+		} else if (!strncmp(argv[1], "server", 6)) {
 			logFileName = "server.txt";
 			mode = SERVER_MODE;
 		}
+	} else {
+		usage(argv[0]);
+		modeless = true;
+		goto leave;
+	}
 
 	// putting this lower down to circumvent the terminal brick when the
 	// socket was already in use results in all network functonality no
@@ -85,9 +102,6 @@ main(int argc, char *argv[])
 	// there was already content in the log file
 	linePos = linesInFile(logFileName) - LOG_LENGTH + 1;
 
-	char *userInput = new char[1024];
-	bool exit = false;
-
 	switch (mode) {
 	case CLIENT_MODE:
 		writeToFile(logFileName, "CLIENT MODE");
@@ -161,11 +175,22 @@ leave:
 		closeServer();
 		break;
 	default:
-		puts("Warn: program appears to have successfully finished without ever setting "
-		     "mode.");
+		if (!modeless) {
+			puts("Warn: program appears to have successfully finished without ever "
+			     "setting mode.");
 			return 1;
+		}
 		break;
 	}
 
 	return 0;
 }
+
+void
+usage(char *progname)
+{
+	printf("\x1b[1mUsage:\x1b[0m\n"
+	       "\t%s client\t\x1b[3m# run as client\x1b[0m\n"
+	       "\t%s server\t\x1b[3m# run as server\x1b[0m\n",
+	       progname, progname);
+}