Types are fundamental to all programming in C++.
类型是 C++ 程序设计的基础。
Each type defines the storage requirements and the operations that may be performed on all objects of that type. The language provides a set of fundamental built-in types such as int and char. These types are closely tied to their representation on the machine's hardware.
每种类型都定义了其存储空间要求和可以在该类型的所有对象上执行的操作。C++ 提供了一组基本内置类型，如 int、char 等。这些类型与它们在机器硬件上的表示方式紧密相关。
Types can be nonconst or const; a const object must be initialized and its value may not be changed. In addition, we can define compound types, such as references. A reference provides another name for an object. A compound type is a type that is defined in terms of another type.
类型可以为 const 或非 const；const 对象必须要初始化，且其值不能被修改。另外，我们还可以定义复合类型，如引用。引用为对象提供了另一个名字。复合类型是用其他类型定义的类型。
The language lets us define our own types by defining a class. The library uses the class facility to provide a set of higher-level abstractions such as the IO and string types.
C++ 语言支持通过定义类来自定义类型。标准库使用类设施来提供一组高级的抽象概念，如 IO 和 string 类型。
C++ is a statically typed language: Variables and functions must be declared before they are used. A variable can be declared many times but defined only once. It is almost always a good idea to initialize variables when you define them.