diff --git a/TinySTL/Utility.h b/TinySTL/Utility.h
index 0ee6a0c..6ad7de6 100644
--- a/TinySTL/Utility.h
+++ b/TinySTL/Utility.h
@@ -1,6 +1,8 @@
 #ifndef _UTILITY_H_
 #define _UTILITY_H_
 
+#include "Algorithm.h"
+
 namespace TinySTL{
 	//************ [swap] ***************
 	template<class T>
@@ -19,7 +21,80 @@ namespace TinySTL{
 		T1 first;
 		T2 second;
 	public:
-
+		pair(){}
+		template<class U, class V> 
+		pair(const pair<U, V>& pr);
+		pair(const first_type& a, const second_type& b);
+		pair& operator= (const pair& pr);
+		void swap(pair& pr);
+	public:
+		template <class T1, class T2>
+		friend bool operator== (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend bool operator!= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend bool operator<  (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend bool operator<= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend bool operator>  (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend bool operator>= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs);
+		template <class T1, class T2>
+		friend void swap(pair<T1, T2>& x, pair<T1, T2>& y);
+		
 	};
+	template<class T1, class T2>
+	template<class U, class V>
+	pair<T1, T2>::pair(const pair<U, V>& pr) :first(pr.first), second(pr.second){}
+	template<class T1, class T2>
+	pair<T1, T2>::pair(const first_type& a, const second_type& b) : first(a), second(b){}
+	template<class T1, class T2>
+	pair<T1, T2>& pair<T1, T2>::operator =(const pair<T1, T2>& pr){
+		if (this != &pr){
+			first = pr.first;
+			second = pr.second;
+		}
+		return *this;
+	}
+	template<class T1, class T2>
+	void pair<T1, T2>::swap(pair<T1, T2>& pr){
+		TinySTL::swap(first, pr.first);
+		TinySTL::swap(second, pr.second);
+	}
+
+	template <class T1, class T2>
+	bool operator== (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return lhs.first == rhs.first && lhs.second == rhs.second;
+	}
+	template <class T1, class T2>
+	bool operator!= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return !(lhs == rhs);
+	}
+	template <class T1, class T2>
+	bool operator<  (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return lhs.first<rhs.first || (!(rhs.first<lhs.first) && lhs.second<rhs.second);
+	}
+	template <class T1, class T2>
+	bool operator<= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return !(rhs<lhs);
+	}
+	template <class T1, class T2>
+	bool operator>(const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return rhs<lhs;
+	}
+	template <class T1, class T2>
+	bool operator>= (const pair<T1, T2>& lhs, const pair<T1, T2>& rhs){
+		return !(lhs<rhs);
+	}
+	template <class T1, class T2>
+	void swap(pair<T1, T2>& x, pair<T1, T2>& y){
+		x.swap(y);
+	}
+	// ******* [make_pair] ************
+	template<class U, class V>
+	pair<U, V> make_pair(const U& u, const V& v){
+		return pair<U, V>(u, v);
+	}
 }
 #endif
\ No newline at end of file