mq日提交14-16题

src/群友提交/第14题/mq日.cpp

@@ -0,0 +1,17 @@
+#include <iostream>
+
+namespace ss
+{
+	int a = 0;
+	namespace s
+	{
+		int& x = a;
+	}
+}
+
+int main()
+{
+	::ss::s::x = 100;
+	// todo..
+	std::cout << ss::a << '\n';
+}

src/群友提交/第15题/mq日.cpp

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+#include <algorithm>
+#include <functional>
+#include <iostream>
+#include <ranges>
+#include <vector>
+#include <iterator>
+// 为std::vector增加一个自定义的赋值函数
+template <typename T>
+	requires std::disjunction_v<std::is_integral<T>, std::is_floating_point<T>>
+class vector : public std::vector<T>
+{
+public:
+	using std::vector<T>::vector;
+	using std::vector<T>::size;
+	using std::vector<T>::operator[];
+	template <typename E>
+	vector<T> &operator=(const E &e)
+	{
+		const auto count = std::min(size(), e.size());
+		this->resize(count);
+		for (std::size_t idx{0}; idx < count; ++idx)
+		{
+			this->operator[](idx) = e[idx];
+		}
+		return *this;
+	}
+};
+
+/*
+// 实现表达式模板类及相关函数
+template<...>
+struct vector_expr {
+
+};
+
+// operator+
+// operator-
+// operator*
+// operator/
+*/
+
+template <typename F,typename Expr1,typename Expr2>
+struct vector_expr
+{
+	F f;
+	const Expr1& expr1;
+	const Expr2& expr2;
+	vector_expr(Expr1 &expr1, Expr2 &expr2) :expr1(expr1), expr2(expr2) {}
+	auto size() const
+	{
+		return std::min(expr1.size(), expr2.size());
+	}
+	auto operator[](std::size_t idx) const
+	{
+		return f(expr1[idx], expr2[idx]);
+	}
+};
+
+template <typename Expr1,typename Expr2>
+auto operator+(const Expr1 &lhs, const Expr2 &rhs)
+{
+	return vector_expr<std::plus<>, const Expr1, const Expr2>(lhs, rhs);
+}
+
+template <typename Expr1,typename Expr2>
+auto operator-(const Expr1 &lhs, const Expr2 &rhs)
+{
+	return vector_expr<std::minus<>, const Expr1, const Expr2>(lhs, rhs);
+}
+
+template <typename Expr1,typename Expr2>
+auto operator*(const Expr1 &lhs, const Expr2 &rhs)
+{
+	return vector_expr<std::multiplies<>, const Expr1, const Expr2>(lhs, rhs);
+}
+
+template <typename Expr1,typename Expr2>
+auto operator/(const Expr1 &lhs, const Expr2 &rhs)
+{
+	return vector_expr<std::divides<>, const Expr1, const Expr2>(lhs, rhs);
+}
+//auto operator
+
+int main()
+{
+	auto print = [](const auto &v)
+	{
+		std::ranges::copy(v, std::ostream_iterator<std::ranges::range_value_t<decltype(v)>>{std::cout, ", "});
+		std::cout << std::endl;
+	};
+	const vector<double> a{1.2764, 1.3536, 1.2806, 1.9124, 1.8871, 1.7455};
+	const vector<double> b{2.1258, 2.9679, 2.7635, 2.3796, 2.4820, 2.4195};
+	const vector<double> c{3.9064, 3.7327, 3.4760, 3.5705, 3.8394, 3.8993};
+	const vector<double> d{4.7337, 4.5371, 4.5517, 4.2110, 4.6760, 4.3139};
+	const vector<double> e{5.2126, 5.1452, 5.8678, 5.1879, 5.8816, 5.6282};
+
+	{
+		vector<double> result(6);
+		for (std::size_t idx = 0; idx < 6; idx++)
+		{
+			result[idx] = a[idx] - b[idx] * c[idx] / d[idx] + e[idx];
+		}
+		print(result);
+	}
+	{
+		vector<double> result(6);
+		result = a - b * c / d + e; // 使用表达式模板计算
+		print(result);
+	}
+	return 0;
+}

src/群友提交/第16题/mq日.cpp

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+#include <iostream>
+
+#define BY_NAME(func) [](auto &&...args) { return func(std::forward<decltype(args)>(args)...); }
+
+template <typename F, class... Args>
+auto foo(F f, Args &&...args)requires (std::is_invocable_v<F, Args...>)
+{
+	return f(std::forward<Args>(args)...);
+}
+
+int main()
+{
+	const auto result = foo(BY_NAME(std::min), 2, 3);
+	std::cout << result << '\n';
+}