diff --git a/tennis.c b/tennis.c
index 3148841..fee55a7 100644
--- a/tennis.c
+++ b/tennis.c
@@ -174,6 +174,14 @@ int validate_entry(const char *entry) {
     return decode_data(&code);
 }
 
+static void print_code(code_t *code) {
+    for (int j = 0; j < 9; j++) {
+        int index = code->code[j];
+        printf("%c", lut[index][0]);
+    }
+    printf("\n");
+}
+
 static u64 prng_state = 1;
 static u32 prng() {
     prng_state = 3935559000370003845 * prng_state + 1;
@@ -189,25 +197,19 @@ int bruteforce() { // with a fixed seed, this is useful for testing.
         }
         if (decode_data(&code)) {
             found++;
-            for (int j = 0; j < 9; j++) {
-                int index = code.code[j];
-                printf("%c", lut[index][0]);
-            }
-            printf("\n");
+            print_code(&code);
         }
     }
     return 1;
 }
 
+#ifndef TENNIS_NO_MAIN
 int main(int argc, char **argv) {
     if (argc == 1) {
         // self-test with codes known before this program was written.
 #define TEST(entry) if (!validate_entry(entry)) return -1
         TEST("48HWOR482");
         TEST("5G3LTQ5GN");
-        //TEST("5PURGR5PM");
-        //TEST("6PJEGRGP5");
-        //TEST("8GYUHR86F");
         TEST("A3W5KQA3C");
         TEST("ARM6JQARU");
         TEST("E880MPE8K");
@@ -234,7 +236,6 @@ int main(int argc, char **argv) {
         TEST("WQJEGRWQ5");
         TEST("WRWQARWRC");
         TEST("YQJEGRYQ5");
-        //TEST("ZKZLZKNNR");
 #undef TEST
         return 0;
     }
@@ -246,6 +247,7 @@ int main(int argc, char **argv) {
     for (int i = 1; i < argc; i++) {
         const char *arg = argv[i];
         if (strlen(arg) == 9) {
+            //if (validate_entry(arg)) printf("%s\n", arg);
             invalid_count += !validate_entry(arg);
         } else if (!strcmp(arg, "bruteforce")) {
             invalid_count += !bruteforce();
@@ -257,11 +259,7 @@ int main(int argc, char **argv) {
             if (code_i >= 7) {
                 code_i = 0;
                 if (encode_data(&code)) {
-                    for (int j = 0; j < 9; j++) {
-                        int index = code.code[j];
-                        printf("%c", lut[index][0]);
-                    }
-                    printf("\n");
+                    print_code(&code);
                 } else {
                     invalid_count++;
                 }
@@ -270,3 +268,4 @@ int main(int argc, char **argv) {
     }
     return invalid_count;
 }
+#endif