diff --git a/convert.cc b/convert.cc
index 7ee9677..d34f84d 100755
--- a/convert.cc
+++ b/convert.cc
@@ -25,7 +25,7 @@ int main(int argc, char* argv[]){
         	{"src", required_argument, NULL, 's'},
         	{"lmdb", no_argument, NULL, 'l'},
         	{"help", no_argument, NULL, 'h'},
-		{0}
+        	{0, 0, 0, 0}
 	};
 	int option_index = 0;
 	while (1) {
@@ -54,18 +54,28 @@ int main(int argc, char* argv[]){
 
 
 	DB_ * x = new Libdb();
-	x->connect_database(src);
+	if (!x->connect_database(src)) {
+	// error is printed in the connect_database function
+		delete x;
+		return 1;
+	}
 	DB_ *b;
 	if (lmdb)
 		b = new LMDB_();
 	else
 		b = new GDBM_();
-	b->create_database(dst);
+	if (!b->create_database(dst)) {
+		std::cerr<<"Failed to create destination database\n";
+		delete x;
+		delete b;
+		return 1;
+	}
 	if (!b->fill_database(x)){
 		std::cerr<<"database filling failed\n";
+		delete x;
+		delete b;
 		return 1;
 	}
-    	b->close_db();
 	delete x;
 	delete b;
 	return 0;
diff --git a/convert_db.h b/convert_db.h
index 7bc8dfa..9e8cf25 100644
--- a/convert_db.h
+++ b/convert_db.h
@@ -37,8 +37,9 @@ class DB_ {
 		virtual bool create_database(std::string name);
 		bool create_db();
 		virtual bool fill_database(DB_ * old_database);
-		virtual void close_db();
+		virtual void close_db() = 0;
 		virtual DBC * get_database();
+		virtual ~DB_();
 };
 /*
  * Libdb class needs only open and read data from libdb database
@@ -53,6 +54,8 @@ class Libdb: public DB_ {
 		Libdb();
 		bool connect_database(std::string path);
 		DBC * get_database();
+		void close_db();
+		~Libdb();
 };
 /*
  * GDBM class provides API for GDBM, allowes to open and create and fill gdbm database
@@ -69,6 +72,7 @@ class GDBM_: public DB_ {
 		bool create_database(std::string name);
 		bool fill_database(DB_ * old_database);
 		void close_db();
+		~GDBM_();
 };
 //https://github.com/LMDB/lmdb/blob/mdb.master/libraries/liblmdb/mtest2.c
 //further inspiration
@@ -86,5 +90,6 @@ class LMDB_: public DB_ {
 		bool create_database(std::string name);
 		bool fill_database(DB_ * old_database);
 		void close_db();
+		~LMDB_();
 };
 
diff --git a/db.cc b/db.cc
index 932d517..ee8962c 100644
--- a/db.cc
+++ b/db.cc
@@ -1,10 +1,5 @@
 #include "convert_db.h"
 
-
-
-Libdb::Libdb(){
-	database_type = DB_type::LIBDB;
-};
 bool DB_::connect_database(std::string){
 	return false;
 }
@@ -21,6 +16,14 @@ DBC * DB_::get_database() {
 	return NULL;
 }
 void DB_::close_db(){}
+
+DB_::~DB_() {
+}
+
+Libdb::Libdb(){
+	database_type = DB_type::LIBDB;
+};
+
 bool Libdb::connect_database(std::string path){
 	DB * db;
 	int status;
@@ -48,6 +51,15 @@ DBC * Libdb::get_database(){
 	return this->cursorp;
 }
 
+void Libdb::close_db() {
+	cursorp->close(cursorp);
+	db->close(db, 0);
+}
+
+Libdb::~Libdb() {
+	close_db();
+}
+
 GDBM_::GDBM_(){
 	database_type = DB_type::GDBM;
 }
@@ -81,6 +93,8 @@ bool GDBM_::fill_database(DB_ * old_database){
 		if (status != 0)
 			return false;
 	}
+	free(data_db);
+	free(key_db);
 	return true;
 }
 
@@ -88,6 +102,10 @@ void GDBM_::close_db(){
 	gdbm_close(this->f);
 }
 
+GDBM_::~GDBM_() {
+	close_db();
+}
+
 LMDB_::LMDB_(){
 	database_type = DB_type::LMDB;
 
@@ -161,4 +179,6 @@ void LMDB_::close_db(){
 	mdb_env_close(this->lmdb_database);
 }
 
-
+LMDB_::~LMDB_() {
+	close_db();
+}