First knowledge of Objective-c

First, learn about OC before

Introduction to OC Syntax

• Keywords begin with @;
• The string starts with @, such as NSLog (@ "I love iOS.");
• Import can automatically prevent the contents of the file from being copied repeatedly;

If you are editing the OC program at the terminal, you must note the following compiled link directive:

• Compiling cc–c main.m
• Link cc main.o–framework Foundation
• Run./a.out

The role of the Foundation framework:

• Develop the necessary framework for OC, IOS, MAC programs
• This framework contains a number of commonly used APIs (application programming interfaces)
• The framework contains a lot of header files, if you want to use the contents of the entire framework, including its main header file can be

Two, a simple example of creating objects based on the OC class

1 #import<Foundation/Foundation.h>2 //definition of car class3 @interfaceCar:nsobject4 {5     @public6     intSpeed ;7     intWheels;8 9 }Ten- (void) run; One @end  A //The realization of car class - @implementationCar -  the- (void) run{ -NSLog (@"A car with%d wheels is runing"); - } - @end +  - intMain () + { ACar *p =[carNew];//the P pointer points to the new object created atP->speed = -; -P->wheels =4; -[P run];//sends a run message message mechanism to the car object that was created -}

Note The above procedures:

1. Declare the function in the Declaration, in the implementation of the implementation of writing methods;
2. Methods and functions are not a thing;
3. The property value is initialized to 0 by default;
4. Add "NSObject" after the class you created to allow car to have the ability to create objects;
5. car* p =[car New] is a p pointer pointing to the in-memory Car object;
6. [P run] sends the run message, the message mechanism;

The benefits of object-oriented encapsulation:

• Closer to the way people think;
• You just need to focus on the object and don't need to follow the steps.

First knowledge of Objective-c