Building blocks of the C++ language

• Functions — reusable procedures implementing a specific task
• Classes — user-defined types bundling data and behavior
• Objects — instances of classes that exist at runtime
• Namespaces — logical grouping of identifiers to avoid name collisions
• Templates — generic programming mechanism for generating code for many types
• Modules (C++20+) — compiled units of code replacing header-centric dependency model
• Headers & source files — physical organization of code