diff --git a/cpp/mwmatching.h b/cpp/mwmatching.h
index 4abcd22..b32a9e3 100644
--- a/cpp/mwmatching.h
+++ b/cpp/mwmatching.h
@@ -482,12 +482,10 @@ struct MatchingContext
     /** Count the number of vertices in the graph. */
     static VertexId count_num_vertex(const std::vector<EdgeT>& edges)
     {
-        const VertexId max_num_vertex = std::numeric_limits<VertexId>::max();
-
         VertexId num_vertex = 0;
         for (const Edge<WeightType>& edge : edges) {
             VertexId m = std::max(edge.vt.first, edge.vt.second);
-            assert(m < max_num_vertex);
+            assert(m < std::numeric_limits<VertexId>::max());
             num_vertex = std::max(num_vertex, m + 1);
         }
 
@@ -1840,7 +1838,7 @@ struct MatchingContext
                 // Count the number of vertices inside this blossom.
                 VertexId blossom_num_vertex = 0;
                 for_vertices_in_blossom(blossom,
-                    [&blossom_num_vertex](VertexId x) {
+                    [&blossom_num_vertex](VertexId) {
                         ++blossom_num_vertex;
                     });
 
@@ -2070,10 +2068,8 @@ template <typename WeightType>
 std::vector<Edge<WeightType>> adjust_weights_for_maximum_cardinality_matching(
     const std::vector<Edge<WeightType>>& edges_in)
 {
-    const WeightType min_safe_weight =
-        std::numeric_limits<WeightType>::min() / 4;
-    const WeightType max_safe_weight =
-        std::numeric_limits<WeightType>::max() / 4;
+    const WeightType min_safe_weight = std::numeric_limits<WeightType>::min() / 4;
+    const WeightType max_safe_weight = std::numeric_limits<WeightType>::max() / 4;
 
     // Copy edges.
     std::vector<Edge<WeightType>> edges(edges_in);
@@ -2086,7 +2082,7 @@ std::vector<Edge<WeightType>> adjust_weights_for_maximum_cardinality_matching(
     // Count number of vertices.
     // Determine minimum and maximum edge weight.
     VertexId num_vertex = 0;
-    WeightType min_weight = edges.first().weight;
+    WeightType min_weight = edges.front().weight;
     WeightType max_weight = min_weight;
 
     const VertexId max_num_vertex = std::numeric_limits<VertexId>::max();