First OC Class

1. How do I declare a class?

Format:

1 @interface People:nsobject 2 {3      // instance Variable 4 }5     // declaration of class 6@end

Attention:

1. Must start with @interface and end with @end.
2. The declaration of the member variable must be written in curly braces between @interface and @end
3. The declaration of the method must be under {} and cannot be written in {}

2. How do I implement a class?

Format:

1 @implementation people 2     // implementation of the class 3 @end

Attention:

• 1. Must start with @implementation, @end end
• 2. The class name must be consistent with the declaration

3. How do I create an object?

Example: people * p = [people new]

Attention:

[People new] has done three things:

1. Opens up a new piece of storage space in heap memory
2. Initializing a member variable (a property written in a class declaration brace is called a member variable, also known as an instance variable)
3. Return pointer address

4. Points of attention of the object:

1. • You can access the members of an object by using object-by-member (notice that the declaring property is: @public).
   • Each object has a property of its own.
   • A member of one of the objects was modified. Not related to another object

First OC Class