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As software increasingly large-scale, complex systems often need to be divided into small part of the design is very important programming interface, practical programming, the programming interface designed to make the first software system to obtain reasonable division of responsibilities, good interface design can reduce the interdependence of the various parts of the system, to improve the cohesion of the constituent units, reduce the degree of coupling between the constituent units, thereby improving the maintenance and expansion of the system.
API is an interface, the program has an important role in the interaction, and the SDK and API has a close relationship.
API
Concept (1) API's
API that is "Application Programming Interface", are some of the pre-defined function, intended to serve as "interface" communication two different things, the ability to provide a software or hardware based on a set of routines to access applications and developers, You do not need to access the source code, or to understand the details of the inner workings.
In fact, someone else has already written a function of a specific function can be achieved, but you only need to provide good interfaces according to him, is to call his method, passing parameters he specified, then this function will help you to achieve these functions.
Interface from the interface, in the computer field refers to the local interaction between two different things, you can complete to two different systems, small can go to the two programs. So this so I understand. On this basis, local people and interact with the program, called UI, user interface, mouse and keyboard for all input includes a touch-screen audio input are considered. The program and the program to interface called API, all non-human to non-human interaction are to interact, interact through the so-called API, in fact, transfer data, trigger functions.
(2) API Applications
Sample scenario: If you are a small business, there is a form on the company's Web site is registered to the customer for an appointment. With these you want to make an appointment details, enabling customers to automatically create an event on Google agenda.
API uses: This means that your web server needs to talk directly to the Google server, in the case of grasp given detailed information, application creation activities. After that, your server will be received in response to Google and processed, and then the information is sent back to the browser, for example, to send a really user
Confirmation message.
(3) API product - now also have an API packaged products
Case: Weather Underground sell its weather data API access to others.
Category (4) API's
API is divided into (Windows, Linux, Unix and other systems) system-level API, and non-OS-level custom API. As an effective code package that Microsoft Windows API development model for many commercial applications have been developed by companies learn and develop API functions of some business applications to be published, to facilitate third party extensions. Such as Google, Apple, and Nokia and other handset development API and so on.
API is divided into an open API and private API. As the name suggests, open API that is public to the interface that allows anyone to call it and get to the data behind it, the company will sometimes its public API as an open system, that is to say, the company developed its own system interface standard, when the need to perform system integration, custom application programs, and other operations, all members can be invoked by the source code interface standard, which is referred to as an open interface standard API. That private API interface is not open.
SDK
Concept (1) SDK's
SDK or "Software Development Kit" is generally a collection of software engineers is used for a particular software package, software framework, hardware platform, operating system, application software development build tools. Popular point refers to the tools provided by third-party service providers to realize a function of the software product package.
SDK is usually provided by the professional services firm specialized nature of the collection, such as providing Android development tools, or based on hardware development services. There is also an SDK for software features, such as push technology, image recognition technology, mobile payment technology, voice recognition analysis technology, under the open Internet trend, some of the functionality of the SDK has been used as a product to operate.
Developers do not need to be developed for each product's features, select the appropriate SDK stable service and cost very little experience you can integrate a function in the product.
The difference (2) SDK API and the
SDK is equivalent to the development of integrated tools environment, API is the data interface. Call the API data in the SDK environment.
Indeed SDK includes API definition, a capability is defined API, a code of the interface, the SDK may include this capability, comprising such a norm. But not completely SDK contains only the API and implementation of the API, which is a software toolkit that there are many other auxiliary functions.
The SDK contains the necessary information to use the API, so people also often the only way to develop Windows API to write applications called "SDK programming."
Popular language interpreter
API
Front-end back-end data call a channel, that is, we say vulgar interface, through this channel, you can access to back-end data, but they do not need to call the source code.
SDK
Software engineers to assist the development of certain types of related documents, samples and a collection of tools, the SDK can improve development efficiency, easier access to certain functions.
For example: a product would like to achieve a certain function, you can find the SDK, engineers direct access to the SDK, do not re-developed.
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