__cpp_fold_expressions201603L(C++17)折叠表达式 示例 运行此代码 #include <climits>#include <concepts>#include <cstdint>#include <iostream>#include <limits>#include <type_traits>#include <utility>#include <vector>// 基本用法,在 operator<< 上折叠可变实参template<typename...Args>voidprinter(Args&&...