Resolve some of the warnings in Windows build

This is a preparation compile with `/WX` flag.

Author: vil02

include/CXXGraph/Graph/IO/InputOperation_impl.hpp

@@ -367,7 +367,7 @@ int Graph<T>::readFromBinary(const std::string &filepath, bool readNodeFeatures,
     in.close();
     return 0;
 
-  } catch (const std::exception &e) {
+  } catch (const std::exception &) {
     in.close();
     return -4;
   }

include/CXXGraph/Graph/IO/OutputOperation_impl.hpp

@@ -282,7 +282,7 @@ int Graph<T>::writeToBinary(const std::string &filepath, bool writeNodeFeatures,
     out.close();
     return 0;
 
-  } catch (const std::exception &e) {
+  } catch (const std::exception &) {
     out.close();
     return -2;
   }

test/KahnTest.cpp

@@ -92,7 +92,7 @@ TEST(KahnTest, correct_example_small) {
   ASSERT_TRUE(res.errorMessage.empty());
   ASSERT_EQ(res.nodesInTopoOrder.size(), graph.getNodeSet().size());
 
-  std::unordered_map<CXXGraph::id_t, int> topOrderNodeIds;
+  std::unordered_map<CXXGraph::id_t, size_t> topOrderNodeIds;
   for (size_t i = 0; i < res.nodesInTopoOrder.size(); ++i) {
     topOrderNodeIds[res.nodesInTopoOrder[i].getId()] = i;
   }
@@ -161,7 +161,7 @@ TEST(KahnTest, correct_example_big) {
   ASSERT_TRUE(res.errorMessage.empty());
   ASSERT_EQ(res.nodesInTopoOrder.size(), graph.getNodeSet().size());
 
-  std::unordered_map<CXXGraph::id_t, int> topOrderNodeIds;
+  std::unordered_map<CXXGraph::id_t, size_t> topOrderNodeIds;
   for (size_t i = 0; i < res.nodesInTopoOrder.size(); ++i) {
     topOrderNodeIds[res.nodesInTopoOrder[i].getId()] = i;
   }

test/TopologicalSortTest.cpp

@@ -96,7 +96,7 @@ TEST(TopologicalSortTest, test_3) {
   ASSERT_EQ(res.nodesInTopoOrder.size(), 8);
 
   // check topological order of nodes
-  std::unordered_map<CXXGraph::id_t, int> nodeToOrder;
+  std::unordered_map<CXXGraph::id_t, size_t> nodeToOrder;
   for (size_t i = 0; i < res.nodesInTopoOrder.size(); ++i) {
     nodeToOrder[res.nodesInTopoOrder[i].getId()] = i;
   }