C++20 现代标准深度拆解大典

参考官方标准: ISO/IEC 14882:2020 C++20 Standard
C++20 是继 C++11 之后最宏大的 C++ 标准变革。它引入了四大支柱：Concepts (概念)、Ranges (范围库)、Coroutines (协程) 与 Modules (模块)。

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🐳 容器运行环境 (Runtime Environment)

在标准 Docker 镜像 gcc:13 中执行控制台诊断指令 g++ --version：

📸 Unverified Snapshot📋gcc:13

⏱️ 536msNot verified

gcc (GCC) 13.4.0
Copyright (C) 2023 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

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1. 🧩 Concepts (概念与约束)

在编译期对模板参数实施强约束校验，大幅改善了复杂的模板编译报错信息。

// 关联源码: demos/cpp/cpp20_demo.cpp
template <typename T>
concept Integral = std::is_integral_v<T>;

template <Integral T>
T Add(T a, T b) { return a + b; }

📸 Unverified Snapshot📋gcc:13

⏱️ 1179msNot verified

C++20 Concepts Demo:
Add(10, 20) = 30 [Integral]
Add(3.14, 2.71) = 5.85 [FloatingPoint]