diff --git a/headers/errors.h b/headers/errors.h
index b94151c..43182e9 100644
--- a/headers/errors.h
+++ b/headers/errors.h
@@ -14,15 +14,13 @@
 #include<string>
 #include<stdexcept>
 
-using namespace std;
-
 /*!
  * @class config_error
  * @brief Simple clone of runtime_error to help us handle errors in config management.
  */
-class config_error : public runtime_error {
+class config_error : public std::runtime_error {
 public:
-	explicit config_error(const string& msg);
+	explicit config_error(const std::string& msg);
 };
 
 #endif
diff --git a/headers/game.h b/headers/game.h
index 20a7b5a..56e5c4e 100644
--- a/headers/game.h
+++ b/headers/game.h
@@ -25,8 +25,6 @@
 #include "god.h"
 #include "invadersGrid.h"
 
-using namespace std;
-
 /*!
  * @class Game
  * @brief Main game class
diff --git a/headers/menu.h b/headers/menu.h
index 6cc0e25..157e7bc 100644
--- a/headers/menu.h
+++ b/headers/menu.h
@@ -15,6 +15,8 @@
 #include<vector>
 #include<string>
 
+using namespace std;
+
 /*!
  * @struct Menu
  * @brief menu stuct
diff --git a/headers/pixelManager.h b/headers/pixelManager.h
index 11e7748..894d14f 100644
--- a/headers/pixelManager.h
+++ b/headers/pixelManager.h
@@ -27,8 +27,6 @@
 #include "scoresManager.h"
 #include "mySprite.h"
 
-using namespace std;
-
 typedef nsGui::GlutFont::GlutFonts Font;
 
 /*!
diff --git a/headers/utils.h b/headers/utils.h
index fb08df9..b4ef375 100644
--- a/headers/utils.h
+++ b/headers/utils.h
@@ -33,8 +33,6 @@
 #define DEBUG_INSTR(X)
 #endif
 
-
-using namespace std;
 using nsGraphics::RGBAcolor;
 
 /*!
@@ -50,7 +48,7 @@ enum class WinValue{
 
 typedef nsGraphics::Vec2D Position;
 typedef unsigned playerID;
-typedef future<void> Task;
+typedef std::future<void> Task;
 #define PLAYER1 0
 #define PLAYER2 1
 
diff --git a/src/errors.cpp b/src/errors.cpp
index a415a42..55c93fa 100644
--- a/src/errors.cpp
+++ b/src/errors.cpp
@@ -10,6 +10,8 @@
 
 #include "errors.h"
 
+using namespace std;
+
 config_error::config_error(const string& msg) : runtime_error(msg) {
 
 }
\ No newline at end of file