diff --git a/src/iomanip.hpp b/src/iomanip.hpp
index 5096c66..47293de 100644
--- a/src/iomanip.hpp
+++ b/src/iomanip.hpp
@@ -41,41 +41,38 @@ namespace sc {
         std::ostream& whiteb(std::ostream& out);
         std::ostream& defaultb(std::ostream& out);
 
-        class grayf {
+        struct grayf {
             int _val;
 
-            public:
-                grayf(int val);
-                friend std::ostream& operator<<(std::ostream& out, const grayf& obj);
+            grayf(int val);
         };
 
-        class grayb {
+        struct grayb {
             int _val;
 
-            public:
-                grayb(int val);
-                friend std::ostream& operator<<(std::ostream& out, const grayb& obj);
+            grayb(int val);
         };
 
-        class rgbf {
+        struct rgbf {
             int _r;
             int _g;
             int _b;
 
-            public:
-                rgbf(int r, int g, int b);
-                friend std::ostream& operator<<(std::ostream& out, const rgbf& obj);
+            rgbf(int r, int g, int b);
         };
 
-        class rgbb {
+        struct rgbb {
             int _r;
             int _g;
             int _b;
 
-            public:
-                rgbb(int r, int g, int b);
-                friend std::ostream& operator<<(std::ostream& out, const rgbb& obj);
+            rgbb(int r, int g, int b);
         };
+
+        std::ostream& operator<<(std::ostream& out, const grayf& obj);
+        std::ostream& operator<<(std::ostream& out, const grayb& obj);
+        std::ostream& operator<<(std::ostream& out, const rgbf& obj);
+        std::ostream& operator<<(std::ostream& out, const rgbb& obj);
     }
 }
 
diff --git a/src/utils.hpp b/src/utils.hpp
index ee58410..e9afd39 100644
--- a/src/utils.hpp
+++ b/src/utils.hpp
@@ -36,14 +36,13 @@ namespace sc {
 
     namespace io {
 
-        class clear_line {
+        struct clear_line {
             const term& _term;
 
-            public:
-                clear_line(const term& t);
-                friend std::ostream& operator<<(std::ostream& out, const clear_line& obj);
+            clear_line(const term& t);
         };
 
+        std::ostream& operator<<(std::ostream& out, const clear_line& obj);
     }
 }