refactor

.gitignore

@@ -32,3 +32,6 @@
 
 # ctags
 *tags*
+
+# vim
+*.swp

ch16/ex16.53.54.55/main.cpp

@@ -1,7 +1,8 @@
 /***************************************************************************
  *  @file       main.cpp
- *  @author     Alan.W
+ *  @author     Yue Wang
  *  @date       16  Feb 2014
+                Aug, 2015
  *  @remark     This code is for the exercises from C++ Primer 5th Edition
  *  @note
  ***************************************************************************/
@@ -12,7 +13,7 @@
 //!
 //! Exercise 16.54:
 //! What happens if we call print on a type that doesn’t have an << operator?
-//  didn't compile.
+//  It didn't  compile.
 //!
 //! Exercise 16.55:
 //! Explain how the variadic version of print would execute if we declared
@@ -21,49 +22,26 @@
 //  error: no matching function for call to 'print(std::ostream&)'
 //!
 
-
 #include <iostream>
 
-class Foo
-{};
-
-//! function to end the recursion and print the last element
-//! this function must be declared before the variadic version of
-//! print is defined
+// trivial case 
 template<typename T>
-std::ostream& print(std::ostream& os, const T& t)
+std::ostream& print(std::ostream& os, T const& t)
 {
     return os << t;
-    //!           ^
-    //! note: no seperator after the last element in the pack
 }
-
-
-//! this version of print will be called for all but the last element in the pack
+// recursion
 template<typename T, typename... Args>
-std::ostream&
-print(std::ostream &os, const T &t, const Args&... rest)
+std::ostream& print(std::ostream& os, T const& t, Args const&... rest)
 {
-    //! print the first argument
-    os << t << ",";
-
-    //! recursive call; print the other arguments
-    return print(os,rest...);
+    return print(os << t << ", ", rest...);
 }
 
-
 int main()
 {
-    //! printing one argument
-    //print(std::cout, 1);
-
-    //! printing two arguments
-    print(std::cout, 1,2);
-
-    //! printing 5 arguments
-    //print(std::cout, 1,2,3,4,"sss");
-
-    //Foo foo,bar;
-    //print(std::cout,foo,bar);
+    print(std::cout, 1) << std::endl;
+    print(std::cout, 1, 2) << std::endl;
+    print(std::cout, 1, 2, 3, 4, "sss", 42.4242) << std::endl;
 
+    return 0;
 }