update dir

using/using_typedef.cpp

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+/**
+ * @file using_typedef.cpp
+ * @brief g++ -o using_typedef using_typedef.cpp -std=c++11
+ * 取代typedef，使用using来定义别名
+ * @author 光城
+ * @version v1
+ * @date 2019-08-07
+ */
+
+#include <iostream>
+#include <vector>
+using namespace std;
+
+typedef vector<int> V1;
+using V2 = vector<int>;
+
+
+int main() 
+{
+    int nums1[] = {1,2,3,4,5,6};
+    V1 vec1(nums1,nums1+sizeof(nums1)/sizeof(int));
+    int nums2[] = {5,7,6};
+    V2 vec2(nums2,nums2+sizeof(nums2)/sizeof(int));
+    
+    for(auto i:vec1)
+        cout<<i<<" ";
+    cout<<endl;
+
+    for(auto i:vec2)
+        cout<<i<<" ";
+    cout<<endl;
+
+    return 0;
+}