ADD file via upload

src/question_generator.cpp

@@ -0,0 +1,19 @@
+#include "question_generator.h"
+
+#include <chrono>
+#include <random>
+
+QuestionGenerator::QuestionGenerator() {
+  rng_.seed(std::chrono::steady_clock::now().time_since_epoch().count());
+}
+
+int QuestionGenerator::GetRandomNumber(int min, int max) {
+  std::uniform_int_distribution<int> dist(min, max);
+  return dist(rng_);
+}
+
+char QuestionGenerator::GetRandomOperator(const std::vector<char>& operators) {
+  if (operators.empty()) return '+';
+  std::uniform_int_distribution<int> dist(0, operators.size() - 1);
+  return operators[dist(rng_)];
+}