1-ios_C-1

1.short cut

  shift + command + 4 = screen capture

  command + delete = Delete

  command + / = annotation

2.we can download the apps from "www.macx.cn"

3.names

  Orgnization Name:your company's name.

  Oragization Identifier:the exclusive identifier of your company(normaly reverse the realm name) 

  Bundle Identifier:the Application's identifier

4.plcacholder

%d

%c

%f

%lf

something about the placeholder like "%02d", and i don't think it is important,so skip it.

5.scanf

scanf("%1",&i)

we can change the vars in RAM the principle of scanf is that when we input a "/n" the scanf will match the input content one by one.

sum

replace the language with SIGNAL is efficient.