RandNFA: Correctly create char alphabet

alib2algo/src/automaton/generate/RandomAutomatonFactory.cpp

@@ -28,7 +28,7 @@ automaton::NFA < > RandomAutomatonFactory::generateNFA( size_t statesCount, size
 		throw exception::CommonException("Too big alphabet.");
 	std::vector<alphabet::Symbol> symbols;
-	for(int i = 0; i < 26; i++) symbols.push_back(alphabet::symbolFrom(i + 'a'));
+	for(int i = 0; i < 26; i++) symbols.push_back(alphabet::symbolFrom((char)(i + 'a')));
 	if(randomizedAlphabet) shuffle(symbols.begin(), symbols.end(), std::random_devices::semirandom);
 	std::deque<alphabet::Symbol> alphabet(symbols.begin(), symbols.begin() + alphabetSize);