support bazel complie this project and format code.

learn_class/modern_cpp_30/functionLambda/adder.cpp

@@ -0,0 +1,32 @@
+//
+// Created by light on 20-1-11.
+//
+#include <iostream>
+
+using namespace std;
+
+struct adder {
+  adder(int n) : n_(n) {}
+
+  int operator()(int x) const { return x + n_; }
+
+private:
+  int n_;
+};
+
+int main() {
+  auto add_2 = adder(2);
+
+  // x+2
+  cout << add_2(3) << endl;
+
+  auto t = bind1st(plus<int>(), 2);
+  cout << t(1) << endl;
+  // 上述的C++98
+  binder2nd<plus<int>> a2(plus<int>(), 2);
+  cout << a2(3) << endl;
+
+  cout << [](int x) { return x * x; }(3) << endl;
+  return 0;
+  // lambda表达式默认就是constexpr函数
+}