fix signed-unsigned comparison warnings and add <algorithm> for std::sort

src/swcio.cpp

+#include <algorithm>
 #include <iomanip>
 #include <map>
 #include <sstream>
 #include <unordered_set>
+
 #include <swcio.hpp>
 
 namespace nestmc

tests/test_swcio.cpp

@@ -234,7 +234,7 @@ TEST(swc_parser, input_cleaning)
         is << "2 1 14.566132 34.873772 7.857000 0.717830 1\n";
 
         auto cells = swc_read_cells(is);
-        EXPECT_EQ(2, cells.size());
+        EXPECT_EQ(2u, cells.size());
     }
 
     {
@@ -246,7 +246,7 @@ TEST(swc_parser, input_cleaning)
         is << "4 1 14.566132 34.873772 7.857000 0.717830 1\n";
 
         auto cells = swc_read_cells(is);
-        EXPECT_EQ(2, cells.size());
+        EXPECT_EQ(2u, cells.size());
     }
 
     {
@@ -259,7 +259,7 @@ TEST(swc_parser, input_cleaning)
 
         std::array<cell_record::id_type, 4> expected_id_list = {{ 0, 1, 2, 3 }};
         auto cells = swc_read_cells(is);
-        ASSERT_EQ(4, cells.size());
+        ASSERT_EQ(4u, cells.size());
 
         auto expected_id = expected_id_list.cbegin();
         for (const auto &c : cells) {
@@ -283,7 +283,7 @@ TEST(swc_parser, input_cleaning)
             {{ 0, 1, 2, 3, 4, 5 }};
         std::array<cell_record::id_type, 6> expected_parent_list =
             {{ -1, 0, 1, 1, 0, 4 }};
-        ASSERT_EQ(6, cells.size());
+        ASSERT_EQ(6u, cells.size());
 
         auto expected_id = expected_id_list.cbegin();
         auto expected_parent = expected_parent_list.cbegin();