update: 完成 20 题

Signed-off-by: YdrMaster <[email protected]>

exercises/18_function_template/main.cpp

@@ -0,0 +1,16 @@
+#include "../exercise.h"
+
+// READ: 函数模板 <https://zh.cppreference.com/w/cpp/language/function_template>
+// TODO: 将这个函数模板化
+int plus(int a, int b) {
+    return a + b;
+}
+
+// ---- 不要修改以下代码 ----
+int main(int argc, char **argv) {
+    ASSERT(plus(1, 2) == 3, "plus two int");
+    ASSERT(plus(1u, 2u) == 3u, "plus two unsigned int");
+    ASSERT(plus(1.f, 2.f) == 3.f, "plus two float");
+    ASSERT(plus(1.0, 2.0) == 3.0, "plus two double");
+    return 0;
+}

exercises/19_runtime_datatype/main.cpp

@@ -0,0 +1,45 @@
+#include "../exercise.h"
+#include <cmath>
+
+enum class DataType {
+    Float,
+    Double,
+};
+
+/// @brief Tagged union 即标签化联合体，是联合体的一种常见应用。
+///        Rust enum 在实现上就是标签化联合体。
+struct TaggedUnion {
+    DataType type;
+    // NOTICE: struct/union 可以相互任意嵌套。
+    union {
+        float f;
+        double d;
+    };
+};
+
+// TODO: 将这个函数模板化用于 sigmoid_dyn
+float sigmoid(float x) {
+    return 1 / (1 + std::exp(-x));
+}
+
+TaggedUnion sigmoid_dyn(TaggedUnion x) {
+    TaggedUnion ans{x.type};
+    // TODO: 根据 type 调用 sigmoid
+    return ans;
+}
+
+// ---- 不要修改以下代码 ----
+int main(int argc, char **argv) {
+    TaggedUnion xf{DataType::Float};
+    xf.f = 5.f;
+    auto yf = sigmoid_dyn(xf);
+    ASSERT(yf.type == DataType::Float, "type mismatch");
+    ASSERT(yf.f == 1 / (1 + exp(-5.f)), "sigmoid float");
+
+    TaggedUnion xd{DataType::Double};
+    xd.d = 5.0;
+    auto yd = sigmoid_dyn(xd);
+    ASSERT(yd.type == DataType::Double, "type mismatch");
+    ASSERT(yd.d == 1 / (1 + exp(-5.0)), "sigmoid double");
+    return 0;
+}

exercises/20_class_template/main.cpp

@@ -0,0 +1,109 @@
+#include "../exercise.h"
+
+// READ: 类模板 <https://zh.cppreference.com/w/cpp/language/class_template>
+
+template<class T>
+struct Tensor4D {
+    unsigned int shape[4];
+    T *data;
+
+    Tensor4D(unsigned int const shape_[4], T const *data_) {
+        unsigned int size = 1;
+        // TODO: 填入正确的 shape 并计算 size
+        data = new T[size];
+        std::memcpy(data, data_, size * sizeof(T));
+    }
+    ~Tensor4D() {
+        delete[] data;
+    }
+
+    // 为了保持简单，禁止复制和移动
+    Tensor4D(Tensor4D const &) = delete;
+    Tensor4D(Tensor4D &&) noexcept = delete;
+
+    // 这个加法需要支持“单向广播”。
+    // 具体来说，`others` 可以具有与 `this` 不同的形状，形状不同的维度长度必须为 1。
+    // `others` 长度为 1 但 `this` 长度不为 1 的维度将发生广播计算。
+    // 例如，`this` 形状为 `[1, 2, 3, 4]`，`others` 形状为 `[1, 2, 1, 4]`，
+    // 则 `this` 与 `others` 相加时，3 个形状为 `[1, 2, 1, 4]` 的子张量各自与 `others` 对应项相加。
+    Tensor4D &operator+=(Tensor4D const &others) {
+        // TODO: 实现单向广播的加法
+        return *this;
+    }
+};
+
+// ---- 不要修改以下代码 ----
+int main(int argc, char **argv) {
+    {
+        unsigned int shape[]{1, 2, 3, 4};
+        // clang-format off
+        int data[]{
+             1,  2,  3,  4,
+             5,  6,  7,  8,
+             9, 10, 11, 12,
+
+            13, 14, 15, 16,
+            17, 18, 19, 20,
+            21, 22, 23, 24};
+        // clang-format on
+        auto t0 = Tensor4D(shape, data);
+        auto t1 = Tensor4D(shape, data);
+        t0 += t1;
+        for (unsigned int i = 0; i < sizeof(data) / sizeof(int); i++) {
+            ASSERT(t0.data[i] == data[i] * 2, "Tensor doubled by plus its self.");
+        }
+    }
+    {
+        unsigned int s0[]{1, 2, 3, 4};
+        // clang-format off
+        float d0[]{
+            1, 1, 1, 1,
+            2, 2, 2, 2,
+            3, 3, 3, 3,
+
+            4, 4, 4, 4,
+            5, 5, 5, 5,
+            6, 6, 6, 6};
+        // clang-format on
+        unsigned int s1[]{1, 2, 3, 1};
+        // clang-format off
+        float d1[]{
+            6,
+            5,
+            4,
+
+            3,
+            2,
+            1};
+        // clang-format on
+
+        auto t0 = Tensor4D(s0, d0);
+        auto t1 = Tensor4D(s1, d1);
+        t0 += t1;
+        for (unsigned int i = 0; i < sizeof(d0) / sizeof(int); i++) {
+            ASSERT(t0.data[i] == 7.f, "Every element of t0 should be 7 after adding t1 to it.");
+        }
+    }
+    {
+        unsigned int s0[]{1, 2, 3, 4};
+        // clang-format off
+        double d0[]{
+             1,  2,  3,  4,
+             5,  6,  7,  8,
+             9, 10, 11, 12,
+
+            13, 14, 15, 16,
+            17, 18, 19, 20,
+            21, 22, 23, 24};
+        // clang-format on
+        unsigned int s1[]{1, 1, 1, 1};
+        double d1[]{1};
+
+        auto t0 = Tensor4D(s0, d0);
+        auto t1 = Tensor4D(s1, d1);
+        t0 += t1;
+        for (unsigned int i = 0; i < sizeof(d0) / sizeof(int); i++) {
+            ASSERT(t0.data[i] == t0.data[i] + 1, "Every element of t0 should be incremented by 1 after adding t1 to it.");
+        }
+    }
+}

exercises/exercise.h

@@ -3,37 +3,13 @@
 
 #include <iostream>
 
-template<class T>
-struct Colorful {
-    int color;
-    T value;
-};
-
-template<class T>
-inline std::ostream &operator<<(std::ostream &os, Colorful<T> const &cf) {
-    return os << "\x1b[" << cf.color << 'm' << cf.value << "\x1b[0m";
-}
-
-#define COLORFUL(VALUE, NAME)                   \
-    template<class T>                           \
-    inline Colorful<T> NAME(T &&val) {          \
-        return {(VALUE), std::forward<T>(val)}; \
-    }
-
-COLORFUL(31, red)
-COLORFUL(32, green)
-COLORFUL(33, yellow)
-COLORFUL(34, blue)
-
-#undef COLORFUL
-
 #define ASSERT(COND, MSG)                                                                         \
     if (!(COND)) {                                                                                \
-        std::cerr << red("Assertion failed at line #") << red(__LINE__) << red(": ") << std::endl \
+        std::cerr << "\x1b[31mAssertion failed at line #" << __LINE__ << ": \x1b[0m" << std::endl \
                   << std::endl                                                                    \
                   << #COND << std::endl                                                           \
                   << std::endl                                                                    \
-                  << green("Message:") << std::endl                                               \
+                  << "\x1b[34mMessage:\x1b[0m" << std::endl                                       \
                   << std::endl                                                                    \
                   << MSG << std::endl                                                             \
                   << std::endl;                                                                   \

exercises/xmake.lua

@@ -58,4 +58,13 @@ target("exercise16")
 target("exercise17")
     add_files("17_class_virtual_destruct/main.cpp")
 
--- TODO: template; array; vector; deque; map; transform; accumulate; fs; thread; mutex;
+target("exercise18")
+    add_files("18_function_template/main.cpp")
+
+target("exercise19")
+    add_files("19_runtime_datatype/main.cpp")
+
+target("exercise20")
+    add_files("20_class_template/main.cpp")
+
+-- TODO: array; vector; deque; map; forward_list; transform; accumulate; fs; thread; mutex;

learn/summary.cpp

@@ -6,7 +6,7 @@
 #include <sstream>
 #include <vector>
 
-constexpr auto MAX_EXERCISE = 17;
+constexpr auto MAX_EXERCISE = 20;
 
 int main(int argc, char **argv) {
     if (argc == 1) {