The first day of IOS learning, and the first day of IOS Learning
Originally engaged in. NET developers have been reluctant to switch to IOS. After complicated inner struggles, they finally have the courage to resign and study IOS. Now they have become unemployed and add students and dogs. I hope that after four months of study, I can get the desired salary. The following are the learning notes during the learning process. In order to make it easier for you to view them in the future, and also hope to provide some help for IOS beginners, you are prepared to record the learning notes for IOS throughout the learning phase.
IOS Learning (C Language) knowledge point sorting notes in the first week
---------------- Notes on the first day ------------------
1. Mac terminal operation commands
1) The tab key can be automatically filled
2) command name + [Command Options] + [command parameters]
3) pwd shows the path of the current directory/File
4) ls displays the files and Folder Information in the current folder.
5) ls-a displays all the files and folders in the current folder, including hidden files.
6) cd enters the file or folder cd + directory name cd .. the parent directory is returned.
7) create a folder mkdir + folder name
8) touch creates a file touch + file name
9) cat displays the file content cat + file name
10) cp copy file cp-rf copy folder
(Note: When copying a file/folder, it must be in the directory path where the current file/folder is located)
11) rm delete file rm + file name rm-rf Delete folder (note the current directory)
12) change the file/folder name in the mv mobile file or folder mv + file name/folder name path + target path mv
Mv + original file/folder name + new file/folder name
Vim Editor
13) The vim + file name enters the file editing command mode.
13-1) "I" inserts text before the current cursor
13-2) "a" inserts text after the current cursor
13-3) "o" inserts a new line of text under the current cursor
13-4) "O" inserts text on the current cursor
14) Press Esc to exit the editing mode.
15) in vim editing mode, move the cursor to the text and press the x key to delete the text.
16) in vim editing mode, undo the change by u
17): set number display row number: set nonmember close row number display
18) copy a row yy copy multiple lines xyy cut one LINE dd cut multiple lines xdd paste p
19) w: Save the current edited content: q! Exit and do not save the edited content: wq saves the edited content and exits: wq! Save the edited content and exit.
GCC compiler
20) touch test. c. Create a test file and write the Execution Code.
21) gcc-o test. c compile the test file
22)./test run the compiled test
2. Common Xcode shortcut keys
1) CMD +,: Set
2) CMD + R: Run
3) CMD +/: comment a line. Uncomment
4) CMD +]: Right Shift of the code segment
5) CMD + [: Move the code segment to the left
6) CMD + Z: Undo operation
4. main function: the main function. For any C program, each sentence of the main function must end;
5./**/used to comment out multiple lines of code // used to comment out a single line of code
6. In the main function, printf declares in stdio. h to press the Alt key + Click the left mouse button to jump to view the specific implementation.
7. <> Search for the header file "" in the database. Search for the header file locally. If not, search for the header file in the database.
8. int indicates that the number of main rows returns an integer value.
9. Description of formatted strings
1) \ n indicates the carriage return character \ d indicates the Tab character
2) % d indicates a 10-digit integer
3) % f indicates float %. 2f indicates that two decimal places are retained.
4) % s indicates the string type char arr []
5) % c indicates a single character type char
6) % hd indicates short integer short
7) % lf indicates double Precision Floating Point Type
8) % Lf indicates long double Type Dual-precision floating point long double Type
9) % ld indicates long integer long
10) % lld indicates the long type
11) % u indicates an unsigned decimal integer unsigned int
12) % lu indicates a signed long integer unsigned long
13) % o indicates an unsigned octal node.
14) % x indicates an unsigned hexadecimal integer
15) printf ("Format String", parameter). The number of parameters that a string must contain double quotation marks must strictly correspond to the format and number of formatted strings.