1 files changed, 100 insertions, 0 deletions
diff --git a/usth/ICT2.1/labwork/2/Ex1.c b/usth/ICT2.1/labwork/2/Ex1.c
new file mode 100644
index 0000000..b4d5836
--- /dev/null
+++ b/usth/ICT2.1/labwork/2/Ex1.c
@@ -0,0 +1,100 @@
+/*
+ * Train represented using linked list by lisp-like constructs.
+ * This is free and unencumbered software released into the public domain.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+
+#include "construct.h"
+
+#define N 7
+#define LEN_MAX 42
+#define PSNGR_MAX 5	/* this raises the chance of empty vehicle */
+
+struct vehicle {
+	int passengers;
+	char *name;
+};
+
+void free_vehicle(struct vehicle *v)
+{
+	free(v->name);
+	free(v);
+}
+
+struct vehicle *mkvehicle(int passengers, char *name)
+{
+	struct vehicle *v = malloc(sizeof(struct vehicle));
+	v->passengers = passengers;
+	v->name = name;
+	return v;
+}
+
+struct vehicle *rand_vehicle()
+{
+	int len = rand() % LEN_MAX + 2;	/* avoid empty name */
+	char *name = malloc(len--);
+	for (int j = 0; j < len; ++j)
+		name[j] = 'a' + rand() % 26;
+	name[len] = 0;
+	return mkvehicle(rand() % PSNGR_MAX, name);
+}
+
+void print_vehicle(struct vehicle *v)
+{
+	printf("%s (%d passengers)\n", v->name, v->passengers);
+}
+
+void print_train(construct *train)
+{
+	if (train == NULL)
+		return;
+	print_vehicle(car(train));
+	print_train(cdr(train));
+}
+
+/* Remove empty vehicles */
+construct *optimize_train(construct *train)
+{
+	if (train == NULL)
+		return NULL;
+	struct vehicle *first = car(train);
+	construct *rest = cdr(train);
+	free(train);
+
+	if (first->passengers)
+		return cons(first, optimize_train(rest));
+	free_vehicle(first);
+	return optimize_train(rest);
+}
+
+int main()
+{
+	construct *train = NULL;
+
+	srand(time(NULL));
+	for (int i = 0; i < N; ++i)
+		train = cons(rand_vehicle(), train);
+	puts("Initial train:");
+	print_train(train);
+	putchar(10);
+
+	train = optimize_train(train);
+	puts("Optimized train:");
+	print_train(train);
+	putchar(10);
+
+	int index = rand() % length(train);
+	struct vehicle *v = rand_vehicle();
+	while (!v->passengers) {
+		free(v);
+		v = rand_vehicle();
+	}
+	train = insert(v, train, index);
+	printf("Train after inserting a new one at index %d:\n", index);
+	print_train(train);
+
+	return 0;
+}