Objective-C learning Summary

1 objective-C: variable and indirect.

Variables are indirect. By assigning a value to a variable, you only need to modify the value of the variable, instead of changing the appearance of the variable one by one.

Files are indirect. Mainly throughProgramIndirectly reads the data in the file and does not write the data into the program.

Pass hidden variables. For example, self-> fillcolor = C is also an indirect transfer.

2. Int main (INT argc, const char * argv []) Where argc is a command line parameter and the name of argv [0] storage program. Argv [1] stores the first parameter.

 

3. Oop experts: when calling a function, it is not called directly, but indirectly.

4. Procedural programming is built on functions.

5. The object isCode.

6. ID is a pointer and a generic type, which is equivalent to VaR in the C # function.

7. Send a message: the notification object performs some operation [sharp draw]

8. The object points to the function to be operated. For example, the circle object points to the circular area or the calculated area.

9. The object is the message target and needs to be queried to see what type it is. Circle browses its code to find the position of the draw function, and then executes the method of drawing the circle.

10. In objective-C, the method is special.

11. @ interface is used to pass the data members and features of the class to the compiler.

12. If you see the @ symbol in objective-C, you can regard it as an extension of C.

13. In objective-C, "-" indicates the declaration of the method.

14. When declaring implementation methods. For example, ":" In-(void) setcolor :( nsstring) S mainly informs the compiler and the programmer about the following parameters.

15. Use inheritance to avoid redundant code.