abstraction

问题 This question already has answers here : What is abstraction? [closed] (4 answers) Closed 1 year ago . I am confused in between many definitions of abstraction. can any one tell me what is abstraction and how can we achieve it ? 回答1: Abstraction in OOP theory consists in retaining only the relevant aspects of a real world object for a specific problem . Thus we talk about abstraction of the reality . It's a reduction . For example, in the real world we have cats and dogs that are vertebrate

问题 I have the following tightly coupled database access class (repository), that is hard to unit test: class EmployeesRepository : IEmployeeRepository ... public IEnumerable<Employee> GetAllEmployees() { List<Employee> list = new List<Employee>(); try { string connectionString = _secureConfig.Value.MyDbSetting; string sql = "select id, firstname, lastname, entrydate, email from empoyees"; using SqlConnection connection = new SqlConnection(connectionString); using SqlCommand command = new

问题 I have the following tightly coupled database access class (repository), that is hard to unit test: class EmployeesRepository : IEmployeeRepository ... public IEnumerable<Employee> GetAllEmployees() { List<Employee> list = new List<Employee>(); try { string connectionString = _secureConfig.Value.MyDbSetting; string sql = "select id, firstname, lastname, entrydate, email from empoyees"; using SqlConnection connection = new SqlConnection(connectionString); using SqlCommand command = new

来源： https://stackoverflow.com/questions/40126943/adapting-c-sharp-event-containing-ref-parameter

问题 After going through SO questions, I learnt that, Encapsulation is about protecting invariants and hiding implementation details. Abstraction has to do with separating interface from implementation . From class room java training, I learnt that, Encapsulation has following advantages, Why encapsulation is your friend? [1] The implementation is independent of the functionality. A programmer who has the documentation of the interface can implement a new version of the module or ADT independently

问题 I have a class which extends another class as shown below abstract class FooAbstract{ constructor(someProp:any){ this.someProp = someProp; } someProp:any; } class Foo extends FooAbstract{ constructor(prop:any){ super(prop); } someRandomFunction(){ console.log("Something") } } I have an interface which has a function as shown below interface ExampleInterface{ someFunction: (foo:FooAbstract)=>any; } Now I want to implement the interface but want to pass subtype as parameter of the function

问题 Application has higher precedence than abstraction. In this sense, what is lambda calculus abstraction? I'm confused at what there is to have precedence over? 回答1: Lambda abstraction is λx.M , for some variable x and arbitrary term M . Application is (MN) , for some arbitrary terms M and N . Precdence is the question which of several operation is to be performed first if more than one reading is possible because the term is ambiguous due to ommission of brackets. For example in arithmetic,

问题 Application has higher precedence than abstraction. In this sense, what is lambda calculus abstraction? I'm confused at what there is to have precedence over? 回答1: Lambda abstraction is λx.M , for some variable x and arbitrary term M . Application is (MN) , for some arbitrary terms M and N . Precdence is the question which of several operation is to be performed first if more than one reading is possible because the term is ambiguous due to ommission of brackets. For example in arithmetic,

问题 I could not find this question anywhere. Based upon my understanding, Inheritance should/might be the subset of Abstraction. 回答1: First of you should be aware, that here is always some leeway in interpreting such terms and concepts. Below is my take on it. Abstraction is the concept while inheritance is a technical realization. Abstraction in general refers to the leaving out of (unnecessary) details. The opposite direction is concretization. Generalization is also often used in this context

问题 I could not find this question anywhere. Based upon my understanding, Inheritance should/might be the subset of Abstraction. 回答1: First of you should be aware, that here is always some leeway in interpreting such terms and concepts. Below is my take on it. Abstraction is the concept while inheritance is a technical realization. Abstraction in general refers to the leaving out of (unnecessary) details. The opposite direction is concretization. Generalization is also often used in this context