Merge pull request LearningInfiniTensor#10 from DongDongBan/patch-header-ex22

为Ex22添加缺少的头文件<cstring>

Author: YdrMaster

exercises/00_hello_world/main.cpp

@@ -1,11 +1,12 @@
 #include "../exercise.h"
+  
 
 // READ: std streams <https://zh.cppreference.com/w/cpp/io/c/std_streams>
 // READ: 流修饰符 <https://zh.cppreference.com/w/cpp/io/manip>
 // READ: format in cxx20 <https://zh.cppreference.com/w/cpp/utility/format/format>
 
 int main(int argc, char **argv) {
     // TODO: 在控制台输出 "Hello, InfiniTensor!" 并换行
-    std::cout : "Hello, InfiniTensor!" + std::endl;
+    std::cout << "Hello, InfiniTensor!" << std::endl;
     return 0;
 }

exercises/01_variable&add/main.cpp

@@ -5,6 +5,7 @@
 int main(int argc, char **argv) {
     // TODO: 补全变量定义并打印加法运算
     // x ?
+    int x = 3;// 定义变量 x 并赋值为 3
     std::cout << x << " + " << x << " = " << x + x << std::endl;
     return 0;
 }

exercises/02_function/main.cpp

@@ -5,6 +5,7 @@
 // NOTICE: 补充由内而外读法的机翻解释 <https://learn.microsoft.com/zh-cn/cpp/c-language/interpreting-more-complex-declarators?view=msvc-170>
 
 // TODO: 在这里声明函数
+int add(int a, int b);
 
 int main(int argc, char **argv) {
     ASSERT(add(123, 456) == 123 + 456, "add(123, 456) should be 123 + 456");
@@ -16,4 +17,5 @@ int main(int argc, char **argv) {
 
 int add(int a, int b) {
     // TODO: 补全函数定义，但不要移动代码行
+    return a + b;// 返回 a 和 b 的和
 }

exercises/03_argument&parameter/main.cpp

@@ -8,19 +8,19 @@ void func(int);
 // TODO: 为下列 ASSERT 填写正确的值
 int main(int argc, char **argv) {
     auto arg = 99;
-    ASSERT(arg == ?, "arg should be ?");
+    ASSERT(arg == 99, "arg should be 99");
     std::cout << "befor func call: " << arg << std::endl;
     func(arg);
-    ASSERT(arg == ?, "arg should be ?");
+    ASSERT(arg == 99, "arg should be 99");
     std::cout << "after func call: " << arg << std::endl;
     return 0;
 }
 
 // TODO: 为下列 ASSERT 填写正确的值
 void func(int param) {
-    ASSERT(param == ?, "param should be ?");
+    ASSERT(param == 99, "param should be 99");
     std::cout << "befor add: " << param << std::endl;
     param += 1;
-    ASSERT(param == ?, "param should be ?");
+    ASSERT(param == 100, "param should be 100");
     std::cout << "after add: " << param << std::endl;
 }

exercises/04_static/main.cpp

@@ -10,10 +10,10 @@ static int func(int param) {
 
 int main(int argc, char **argv) {
     // TODO: 将下列 `?` 替换为正确的数字
-    ASSERT(func(5) == ?, "static variable value incorrect");
-    ASSERT(func(4) == ?, "static variable value incorrect");
-    ASSERT(func(3) == ?, "static variable value incorrect");
-    ASSERT(func(2) == ?, "static variable value incorrect");
-    ASSERT(func(1) == ?, "static variable value incorrect");
+    ASSERT(func(5) == 5, "static variable value incorrect");
+    ASSERT(func(4) == 6, "static variable value incorrect");
+    ASSERT(func(3) == 7, "static variable value incorrect");
+    ASSERT(func(2) == 8, "static variable value incorrect");
+    ASSERT(func(1) == 9, "static variable value incorrect");
     return 0;
 }

exercises/05_constexpr/main.cpp

@@ -4,12 +4,27 @@ constexpr unsigned long long fibonacci(int i) {
     switch (i) {
         case 0:
             return 0;
+            break;
         case 1:
             return 1;
+            break;
         default:
             return fibonacci(i - 1) + fibonacci(i - 2);
+            break;
     }
 }
+unsigned long long fibonacci2(int n) {
+    if (n == 0) return 0;
+    if (n == 1) return 1;
+
+    unsigned long long a = 0, b = 1;
+    for (int i = 2; i <= n; ++i) {
+        auto temp = a + b;
+        a = b;
+        b = temp;
+    }
+    return b;
+}
 
 int main(int argc, char **argv) {
     constexpr auto FIB20 = fibonacci(20);
@@ -19,7 +34,7 @@ int main(int argc, char **argv) {
     // TODO: 观察错误信息，修改一处，使代码编译运行
     // PS: 编译运行，但是不一定能算出结果……
     constexpr auto ANS_N = 90;
-    constexpr auto ANS = fibonacci(ANS_N);
+    auto ANS = fibonacci2(ANS_N);
     std::cout << "fibonacci(" << ANS_N << ") = " << ANS << std::endl;
 
     return 0;

exercises/06_array/main.cpp

@@ -11,13 +11,13 @@ unsigned long long fibonacci(int i) {
             return 1;
         default:
             // TODO: 补全三目表达式缺失的部分
-            return <condition> ? <cache> : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
+            return (arr[i] != 0) ? arr[i] : (arr[i] = fibonacci(i - 1) + fibonacci(i - 2));
     }
 }
 
 int main(int argc, char **argv) {
     // TODO: 为此 ASSERT 填写正确的值
-    ASSERT(sizeof(arr) == ?, "sizeof array is size of all its elements");
+    ASSERT(sizeof(arr) == 720, "sizeof array is size of all its elements");
     // ---- 不要修改以下代码 ----
     ASSERT(fibonacci(2) == 1, "fibonacci(2) should be 1");
     ASSERT(fibonacci(20) == 6765, "fibonacci(20) should be 6765");

exercises/07_loop/main.cpp

@@ -5,9 +5,9 @@
 // READ: 纯函数 <https://zh.wikipedia.org/wiki/%E7%BA%AF%E5%87%BD%E6%95%B0>
 static unsigned long long fibonacci(int i) {
     // TODO: 为缓存设置正确的初始值
-    static unsigned long long cache[96], cached;
+    static unsigned long long cache[96] = {0,1}, cached = 2;
     // TODO: 设置正确的循环条件
-    for (; false; ++cached) {
+    for (; cached <= i; ++cached) {
         cache[cached] = cache[cached - 1] + cache[cached - 2];
     }
     return cache[i];

exercises/08_pointer/main.cpp

@@ -5,6 +5,15 @@ bool is_fibonacci(int *ptr, int len, int stride) {
     ASSERT(len >= 3, "`len` should be at least 3");
     // TODO: 编写代码判断从 ptr 开始，每 stride 个元素取 1 个元素，组成长度为 n 的数列是否满足
     // arr[i + 2] = arr[i] + arr[i + 1]
+    for (int i = 0 ; i <len - 2; i++) {
+
+        for (int i = 0; i <= len - 3; ++i) {
+            int a = *(ptr + i * stride);
+            int b = *(ptr + (i + 1) * stride);
+            int c = *(ptr + (i + 2) * stride);
+            if (c != a + b) return false;
+        }
+    }
     return true;
 }
 

exercises/09_enum&union/main.cpp

@@ -37,6 +37,7 @@ ColorEnum convert_by_pun(Color c) {
 
     TypePun pun;
     // TODO: 补全类型双关转换
+    pun.c = c;
 
     return pun.e;
 }