diff --git a/toml/parser.hpp b/toml/parser.hpp
index 4bd4b60..26b13b1 100644
--- a/toml/parser.hpp
+++ b/toml/parser.hpp
@@ -1058,7 +1058,7 @@ bool is_valid_forward_table_definition(const value& fwd,
     {
         // table keys always contains all the nodes from the root.
         const auto& tks = tabkeys.unwrap().first;
-        if(std::distance(key_first, key_last) == tks.size() &&
+        if(std::size_t(std::distance(key_first, key_last)) == tks.size() &&
            std::equal(tks.begin(), tks.end(), key_first))
         {
             // the keys are equivalent. it is not allowed.
@@ -1079,7 +1079,7 @@ bool is_valid_forward_table_definition(const value& fwd,
         // a dotted key starts from the node representing a table in which the
         // dotted key belongs to.
         const auto& dks = dotkeys.unwrap().first;
-        if(std::distance(key_curr, key_last) == dks.size() &&
+        if(std::size_t(std::distance(key_curr, key_last)) == dks.size() &&
            std::equal(dks.begin(), dks.end(), key_curr))
         {
             // the keys are equivalent. it is not allowed.
diff --git a/toml/serializer.hpp b/toml/serializer.hpp
index cb150bb..c25f8b2 100644
--- a/toml/serializer.hpp
+++ b/toml/serializer.hpp
@@ -5,6 +5,7 @@
 #include "value.hpp"
 #include "lexer.hpp"
 #include <limits>
+#include <cstdio>
 
 namespace toml
 {
@@ -30,13 +31,12 @@ struct serializer
     }
     std::string operator()(const toml::floating f) const
     {
-        std::string token = [=] {
-            // every float value needs decimal point (or exponent).
-            std::ostringstream oss;
-            oss << std::setprecision(float_prec_) << std::showpoint << f;
-            return oss.str();
-        }();
+        const auto fmt = "%.*g";
+        const auto bsz = std::snprintf(nullptr, 0, fmt, this->float_prec_, f);
+        std::vector<char> buf(bsz + 1, '\0'); // +1 for null character(\0)
+        std::snprintf(buf.data(), buf.size(), fmt, this->float_prec_, f);
 
+        std::string token(buf.begin(), buf.end());
         if(token.back() == '.') // 1. => 1.0
         {
             token += '0';