In programming languages, an abstract type is a type in a nominative type system that can be instantiated directly; a type that is not abstract – which can be instantiated – is called a concrete type.
A: 正确
B: 错误
A: 正确
B: 错误
举一反三
- In programming languages, an abstract type is a type in a nominative type system that can be instantiated directly; a type that is not abstract – which can be instantiated – is called a concrete type. A: 正确 B: 错误
- Every instance of an abstract type is an instance of some concrete subtype.
- The key in the dictionary can't be a dictionary type, but value can be a dictionary type. A: 正确 B: 错误
- Anew type ________. A: is a subclass B: can be derived from an existing type C: can’t be called a derived type D: inherits all features of existing type and has additional features
- Abstracts are classified into different types, which of the following is not listed as one type of abstract? A: Expository abstract B: Structured abstract C: Informative abstract