support bazel complie this project and format code.

learn_class/modern_cpp_30/compilercompute/BUILD

@@ -0,0 +1,27 @@
+# please run `bazel run //learn_class/modern_cpp_30/compilercompute:IF`
+# please run `bazel run //learn_class/modern_cpp_30/compilercompute:factorial`
+# please run `bazel run //learn_class/modern_cpp_30/compilercompute:fmap`
+# please run `bazel run //learn_class/modern_cpp_30/compilercompute:WhileLoop`
+
+load("@rules_cc//cc:defs.bzl", "cc_binary")
+
+cc_binary(
+    name = "IF",
+    srcs = ["IF.cpp"],
+    copts = ["-std=c++17"],
+)
+cc_binary(
+    name = "factorial",
+    srcs = ["factorial.cpp"],
+    copts = ["-std=c++17"],
+)
+cc_binary(
+    name = "fmap",
+    srcs = ["fmap.cpp"],
+    copts = ["-std=c++17"],
+)
+cc_binary(
+    name = "WhileLoop",
+    srcs = ["WhileLoop.cpp"],
+    copts = ["-std=c++17"],
+)

learn_class/modern_cpp_30/compilercompute/IF.cpp

@@ -0,0 +1,43 @@
+//
+// Created by light on 19-12-28.
+//
+
+#include <iostream>
+
+using namespace std;
+
+// 使用template实现IF条件判断
+
+template <bool cond, typename Then, typename Else> struct IF;
+
+template <typename Then, typename Else> struct IF<true, Then, Else> {
+  typedef Then result;
+};
+
+template <typename Then, typename Else> struct IF<false, Then, Else> {
+  typedef Else result;
+};
+
+// 判断奇数与偶数
+template <int N> struct isEven {
+  static const auto RES = IF<N & 1 == 0, true_type, false_type>::result::value;
+};
+
+template <int nums1, int nums2> struct Add_ {
+  static const int value = nums1 + nums2;
+};
+
+template <int nums1, int nums2> struct Sub_ {
+  static const int value = nums1 - nums2;
+};
+
+// 加减
+template <bool cond, int nums1, int nums2> struct addSub {
+  static const auto RES =
+      IF<cond, Add_<nums1, nums2>, Sub_<nums1, nums2>>::result::value;
+};
+
+int main() {
+  cout << isEven<10>::RES << endl;
+  cout << addSub<true, 10, 2>::RES << endl;
+}

learn_class/modern_cpp_30/compilercompute/WhileLoop.cpp

@@ -0,0 +1,57 @@
+//
+// Created by light on 20-1-5.
+//
+
+#include <iostream>
+
+using namespace std;
+
+// 使用template实现while循环
+
+template <bool condition, typename Body> struct WhileLoop;
+
+template <typename Body> struct WhileLoop<true, Body> {
+  typedef
+      typename WhileLoop<Body::cond_value, typename Body::next_type>::type type;
+};
+
+template <typename Body> struct WhileLoop<false, Body> {
+  typedef typename Body::res_type type;
+};
+
+template <typename Body> struct While {
+  typedef typename WhileLoop<Body::cond_value, Body>::type type;
+};
+template <typename Body> using While_t = WhileLoop<Body::cond_value, Body>;
+
+namespace my {
+template <class T, T v> struct integral_constant {
+  static const T value = v;
+  typedef T value_type;
+  typedef integral_constant<T, v> type;
+};
+} // namespace my
+template <int result, int n> struct SumLoop {
+
+  // 循环的条件
+  static const bool cond_value = n != 0;
+
+  // 循环后的结果
+  static const int res_value = result;
+
+  // 循环时的状态
+  typedef my::integral_constant<int, res_value> res_type;
+
+  // 循环执行一次时的状态
+  typedef SumLoop<result + n, n - 1> next_type;
+};
+
+template <int n> struct Sum { typedef SumLoop<0, n> type; };
+
+template <int n> using Sum_t = SumLoop<0, n>;
+
+int main() {
+  cout << While<Sum<6>::type>::type::value << endl;
+  cout << While_t<Sum_t<6>>::type::value << endl;
+  return 0;
+}

learn_class/modern_cpp_30/compilercompute/factorial.cpp

@@ -0,0 +1,20 @@
+//
+// Created by light on 19-12-28.
+//
+
+#include <iostream>
+
+using namespace std;
+
+template <int n> struct factorial {
+  static_assert(n >= 0, "Arg must be non-negative");
+  static const int value = n * factorial<n - 1>::value;
+};
+
+template <> struct factorial<0> { static const int value = 1; };
+
+int main() {
+
+  printf("%d\n", factorial<10>::value);
+  return 0;
+}

learn_class/modern_cpp_30/compilercompute/fmap.cpp

@@ -0,0 +1,34 @@
+//
+// Created by light on 20-1-5.
+//
+
+#include <iostream>
+#include <vector>
+
+using namespace std;
+
+template <template <typename, typename> class OutContainer = vector, typename F,
+          class R>
+auto fmap(F &&f, R &&inputs) {
+  typedef decay_t<decltype(f(*inputs.begin()))> result_type;
+
+  OutContainer<result_type, allocator<result_type>> result;
+
+  for (auto &&item : inputs) {
+    result.push_back(f(item));
+  }
+  return result;
+}
+
+// 对每一个数进行加1操作
+int add_1(int x) { return x + 1; }
+
+int main() {
+  vector<int> v{1, 2, 3, 4, 5};
+  auto result = fmap(add_1, v);
+
+  for (auto item : result)
+    cout << item << " ";
+  cout << endl;
+  return 0;
+}