diff --git a/du4/program.c b/du4/program.c
index 1a263e5..98c19b3 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -1,5 +1,22 @@
 #include <stdio.h>
 
+
+struct car* add_car (struct car* first, const char* target) {
+
+}
+
+void print_train (struct car* first) {
+
+}
+
+void cancel_train (struct car* first) {
+    
+}
+
+struct car* clear_train(struct car* first, const char* target) {
+    
+}
+
 int main() {
     return 0;
 }
\ No newline at end of file