Solved: 40 - Optional

modules/11_cpp17/src/optional.cpp

@@ -2,19 +2,28 @@
 
 namespace cpp17 {
 
-auto safe_divide(int lhs, int rhs) -> std::optional<double> {
+auto safe_divide(const int lhs, const int rhs) -> std::optional<double> {
-    (void)lhs; (void)rhs;
+    if (rhs == 0) {
         return std::nullopt;
     }
+    return std::optional(lhs / static_cast<double>(rhs));
+}
 
 auto find_user(const std::vector<std::string>& users, const std::string& name)
     -> std::optional<std::size_t> {
-    (void)users; (void)name;
+    const auto idx = std::ranges::find(users, name);
+    if (idx == users.end()) {
         return std::nullopt;
     }
+    return std::optional<std::size_t>(std::distance(users.begin(), idx));
+}
 
 auto first_positive(const std::vector<int>& data) -> std::optional<int> {
-    (void)data;
+    for (const auto& elem : data) {
+        if (elem > 0) {
+            return std::optional(elem);
+        }
+    }
     return std::nullopt;
 }