support bazel complie this project and format code.

learn_class/modern_cpp_30/SFINAE/sfinae paper/blending2.cpp

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+//
+// Created by light on 20-1-6.
+//
+
+#include <iostream>
+#include "structData.h"
+
+
+template<typename T, typename=std::string>
+struct hasSerialize : std::false_type {
+
+};
+template<typename T>
+struct hasSerialize<T, decltype(std::declval<T>().serialize())> : std::true_type {
+
+};
+
+template<class T>
+std::string serialize(const T &obj) {
+    // 不加constexpr 报错：error: no member named 'serialize' in 'A'.
+    if constexpr (hasSerialize<T>::value)   // c++17特性
+        return obj.serialize();
+    else
+        return to_string(obj);
+}
+
+int main() {
+    A a;
+    B b;
+    C c;
+
+    // The following lines work like a charm!
+    std::cout << serialize(a) << std::endl;
+    std::cout << serialize(b) << std::endl;
+    std::cout << serialize(c) << std::endl;
+
+}