diff --git a/modules/11_cpp17/src/if_constexpr.cpp b/modules/11_cpp17/src/if_constexpr.cpp
index 71acf71..3c18314 100644
--- a/modules/11_cpp17/src/if_constexpr.cpp
+++ b/modules/11_cpp17/src/if_constexpr.cpp
@@ -5,8 +5,12 @@
 namespace cpp17 {
 
 auto stringify_ints(const std::vector<int>& data) -> std::string {
-    (void)data;
-    return {};
+    auto oss = std::stringstream();
+    for (auto i = 0uz; i < data.size(); ++i) {
+        if (i > 0) oss << ",";
+        oss << data[i];
+    }
+    return oss.str();
 }
 
 }  // namespace cpp17