C++20新增特性：指定初始化器详解与应用

C&＃43;&＃43;20 标准引入了 Designated Initializer。它类似 C# 的 Object Initializer 和 Kotlin 的 apply&＃xff08;scope function&＃xff09;&＃xff0c;允许在仅需要初始化类或结构体的部分成员时&＃xff0c;使用更少的代码即可完成。

#include int main() {struct point {double x &＃61; 0, y &＃61; 0, z &＃61; 0;};struct line_segment {struct point s, t;};const auto print_point &＃61; [](const point& p) {std::cout << "<" << p.x << ", " << p.y << ", " << p.z << ">" << std::endl;};const struct point p{ .x &＃61; 1, .y &＃61; 2, };const struct line_segment s { .s{}, .t{.z &＃61; 1} }; // Chained designators are nonstandard in C&＃43;&＃43;. Hence ".t.z &＃61; 1" instead of ".t{.z &＃61; 1}" will make a Compilation ERROR.print_point(p);print_point(s.s);print_point(s.t);return 0;
}