Computer Programming 1 Lab

2020-09-17

Rules - Assignments

  • DO NOT CHEAT!
  • Both cheater and his partner will be punished.
  • Lock your assignment directory!
  • Discuss, BUT not copy.
  • Exercise will be announced in EVERY TA’s class.

Rules - Mailing Convention

  • Asking questions of TAs via e-mail
  • The subject of mail shall begin with [109cp1] and make it clear.
  • Hi, my code doesn’t work -----> (X) wrong subject.
  • [109cp1] help!! -----> (X) help what?
  • [109cp1] for-loop did’t stop! -----> (O) nice and clear !!
  • Include your signature
    • Remember to append your studentID and your name to the mail.

Rules - Asking a Question in a Smart Way

Before You Ask

  • Try to find an answer by searching the archives of the FB Group or class resources.
  • Try to find an answer by searching the Web.
  • Try to find an answer by asking a skilled friend.

When You Ask

  • Use meaningful, specific subject headers
  • Be explicit about your question
    • Have you tried any test? What problem you think you are facing?
    • DON'T JUST PASTE YOUR CODE SNIPPETS.

Outline

  • Basic Unix Command
  • Basic Vim
  • Lock directory
  • Assignment

Basic UNIX Command

  1. Download pietty (Windows Only)
  2. Connect to ghost.cs.nccu.edu.tw
    Windows: Use Telnet first time, and use SSH afterwards.
    telnet s109XX@ghost.cs.nccu.edu.tw
    MacOS:
    ssh s109XX@ghost.cs.nccu.edu.tw

    s109XX is your ID, the "XX" is the latest two digits of your StudentID

  3. Enter your password

    It is normal for the password you entered not displaying on your window

Basic UNIX Command

  1. Change your password
    $ passwd
  2. Activate your mail service
    $ elm
    then press 'y' three times and 'q' to finish
  3. Setting your enviorment
cp ~g10611/.profile . 
cp ~g10611/.vimrc .  
cp ~g10611/.bashrc .  
exit
  1. Connenct to s109XX@ghost.cs.nccu.edu.tw again (Use SSH this time)

Basic UNIX Command

~ => your home directory
~x => x’s home directory
. => current directory
.. => parent directory

Absolute path: Start with "/"

  • /usr/share/bin
  • /home1/student/stud107/s107xx

Relative path: Path relate to current directory.

  • If current dir is /usr
    test/bin => /usr/test/bin
    li/public => /usr/li/public

Basic UNIX Command

  • ls list files in current directory.
ls
ls -l  # list files details in current directory.
ls -a  # list all files (include hidden files).
ls -la # Both of listing all files with details

Basic UNIX Command

How to create/delete/copy files or directories?

mkdir test 
# Create a directory named "test" in current directory
cp fileX dirY/dirZ
# Copy fileX from current directory to ./dirY/dirZ
cp fileX dirY/fileZ
# Copy fileX from current directory to dirY and rename to fileZ.
cp -r dirX dirY
# Copy dirX from current directory to dirY.
# If dirY doesn't exist, dirY is a copy of dirX.
# If dirY is a directory then there will be a copy of dirX under dirY.

Basic UNIX Command

How to create/delete/copy files or directories?

mv fileA dirB
# Move fileA to dirB.
mv dirA dirB
# If dirB exist, then move dirA under dirB.
# If dirB does not exist, dirA is rename to dirB.
rm fileA
# Remove file fileA (Only for file)
rm -r dirA
# Remove directory dirA and all its contents

Basic UNIX Command - Your Round

  1. Please create a directory named "1091cp1"
    mkdir 1091cp1
  2. Enter directory "1091cp1"
    cd 1091cp1
  3. Please create a directory named "abc"
    mkdir abc
  4. Please rename "abc" to "xyz"
    mv abc xyz
  5. Copy "xyz" and rename it as "jqk"
    cp -r xyz jqk
  6. Please delete directory "xyz" and "jqk"
    rm -r xyz jqk

Basic UNIX Command - Recap

  • Use mkdir to create a directory
  • Use mv to move a directory/file or rename a directory/file
  • Use cp to copy a file and cp -r to copy a directory
  • Use rm for removing file and rm -r for removing directory

Basic UNIX Command - Others

  • The path used on cp, mv, rm, mkdir can be absolute path or relative path.
  • Use pwd to see what the current directory is.
  • Use whoami to see your account's name.
  • Use logout to logout the system. (or you can press Ctrl+D either)
  • Type Ctrl+L to clean your screen
  • Remember, whenever you have problems using Unix, try "man" command.
man ls
man cp

man stands for manual.

Basic Vim

  • Vim is a text editor that you can write texts, codes just like 記事本
  • To use it, you just need to type vim with a filename folowing it, e.g. vim test.txt

    If the file exists, Vim will create one. Otherwise, it will open it.

Vim h:300 center

Basic Vim

  • Vim basically has three modes:
    • Normal Mode:
      • Navigate, Search, Replace, Copy, Paste
    • Insert Mode:
      • Typing
    • Command-Line Mode:
      • Read, Write File...

Vim Modes h:300 right

Basic Vim

  1. Vim starts in normal mode.
  2. Press i to change to Insert mode.
  3. Type some words…
  4. Press ESC back to normal mode.
  5. Press : or / to enter command-line mode. (Save, open file, search text, indenting…etc.)

Vim Modes h:250 upper-right

Basic Vim

  1. In the normal mode of vim, press i to insert mode and type some texts.

  2. When you have done our work, press ESC back to normal mode.

  3. Then type :w xxx.txt to save our work to xxx.txt

  4. Now type :q to exit vim.

  5. ls your files to check if the xxx.txt exists

Basic Vim - Others

  • Use :q! to quit Vim forcibly no matter if you have written your files.

    If you quit without saving your will get a warning

  • Use :x or :wq to write your file and quit Vim with only one command.
  • Use :! to commaand shell command in VI, e.g. :!ls
  • Use :xxx to move cursor to the specific line.

    xxx is the line number

Basic Vim - Your Round

  1. Please create a file named "abc.txt"
    vim abc.txt

  2. Please insert “hello world” at line 3
    i -> Enter Twice -> Type hello world

  3. Please save the file
    :w

  4. Please quit the file
    :q

How to Lock Your Directory?

  1. Create a directory named 1091cp1 at your home directory

    mkdir ~/1091cp1
cd ~

  2. Enter chmod -R 700 1091cp1 to lock your directory.

How to Lock Your Directory?

In UNIX, There are three access levels?

  • Owner => You
  • Group => Accounts in the same group, say, stud109
  • Others => Other guys…

For each level, you can set it permissions:

  • Read (r)
  • Write (w)
  • Execute (x)

How to Lock Your Directory?

Take a look at following ls -l output:

  • g9803 is the owner
  • grad98 is the group
  • The first letter will show - or d which are representing a file or a directory separately.
[g9803@ghost]~ ls -l 
總計 4
-rw-r--r-- 1 g9803 grad98   74 2010-02-04 02:15 100.in
drwxr-xr-x 3 g9803 grad98  512 2010-09-15 11:41 991cp1/
-rw-r--r-- 1 g9803 grad98  672 2010-02-04 00:04 acm100.c
-rw-r--r-- 1 g9803 grad98  507 2010-03-02 15:50 acronym.cpp

How to Lock Your Directory?

  • The following 9 letters like rwxr----- indicates the file's permission
  • The first 3 letters indicate the permission of owner
    • In case rwx, it means user g9803 can read, write, and execute
  • The middle 3 letters indicate the permission of group
    • In case r--, it means the users in group grad98 only can read
  • The last 3 letters indicate the permission of others
    • In case ---, it means others' permission is none.
[g9803@ghost]~ ls -l 
總計 4
-rw-r--r-- 1 g9803 grad98   74 2010-02-04 02:15 100.in
drwxr-xr-x 3 g9803 grad98  512 2010-09-15 11:41 991cp1/
-rw-r--r-- 1 g9803 grad98  672 2010-02-04 00:04 acm100.c
-rw-r--r-- 1 g9803 grad98  507 2010-03-02 15:50 acronym.cpp

How to Lock Your Directory?

chmod_calc h:500 center

Assignment 0

  1. Go to NCCU OJ website and sign up

(Please set your school ID as username, e.g. 109701234)

  1. Click Contests on the menu.
  2. Click the assignment you want to submit (In this week, the assignment is Assignment 0)
  3. Click Problems in the right panel
  4. Click the problem
  5. You could edit the code in VIM, then paste your code at the submit area.
  6. Click Submissions in the right panel to check if you have submitted successfully.

Join FB Group

Any Question?

Course? Assignment? Exercise? TA?