initializer_list VS constructor

Author: Wang Jiazi

C++/C++11/InitializerList/test.cpp

@@ -0,0 +1,35 @@
+#include <string>
+#include <iostream>
+#include <initializer_list>
+
+class People {
+public:
+    People(int id, std::string name):mId(id), mName(name) { std::cout<<"Normal Constructor\n";}
+    People(std::initializer_list<std::pair<int, std::string>> s) {std::cout<<"Initializer_list Constructor\n";}
+
+    People(int, int) {std::cout<<"Normal Constructor2\n";}
+    People(std::initializer_list<int>) {std::cout<<"Initializer_list Constructor2\n";}
+private:
+    int mId;
+    std::string mName;
+};
+
+/*
+"{}" is used to initialize object the constructor whose parameter type is initializer_list should be picked firstly; if failed, then normal constructor is chosen.
+"()" is used to initialize object the constructor whose parameter type is non-initialize_list should be picked.
+*/
+int main()
+{
+
+    People P1={123, "One"}; //Normal Constructor
+    People P2={std::pair<int, std::string>(123, "One"), std::pair<int, std::string>(1234, "Two")}; //Initializer_list Constructor
+    People P3={123, 123}; //Initializer_list Constructor2
+    People P4={123, "a"}; //Normal Constructor
+    People P5={123, 'a'}; //Initializer_list Constructor2
+    People P6(123, 123);  //Normal Constructor2
+/*
+    error: no matching function for call to ‘People::People(std::pair<int, std::basic_string<char> >)’
+    People P7(std::pair<int, std::string>(123, "One")); 
+*/
+    People P7({std::pair<int, std::string>(123, "One")}); //Initializer_list Constructor
+}