Tag 02 Programmierung Day 2

Switch

A Java switch case is like a multi-nested if statement. It's a jump instruction based on fixed values.

switch(i) {
   // after the : comes what has to happen 
   case 1:
       System.out.println("a");
       break;
   case 2:
       System.out.println("c");
       break;
   //and so on.. 
   //otherwise this happens
   default:
       System.out.println("z");
       break;
}

Example: Write a code that tells you the menu of cafeteria based on the weekday.

int weekday = 1;
switch (weekday) {
  case 1:
  System.out.println ("Today we have ravioli.");
  break;
  case 2:
  System.out.println ("Today we have spinach soup");
  break;
  //and so on
  default:
  System.out.println ("Unfortunately, the cafeteria is closed today and there is nothing to eat.");
  break;
}

Shell basics

The servers on which software developers work mostly do not have a graphical user interface. Most software runs on a server and most servers run Linux. As a developer, you must therefore be able to operate Linux in the terminal.

Unix Syntax

<command> -- <option> <parameter>

commands

• ls
• cd path/to/something
• cd ...
• touchcreates an empty file
• echo "Hello" >> text.txt creates a new file text.txt with the entry "Hello"
• mkdir my-folder
• rm -rf my-folder
• pwd print working directory, it's the directory in which the user is currently working in
• mv /home/user/text.txt /destination/ moves text.txt from source folder to a destination folder
• mv text.txt text2.txt renames text.txt into test2.txt

Script

A script is a file containing a sequence of commands that you can run to save you from constantly typing.

****editors:

vim script.sh (opens script.sh with editor vim) nano script.sh (opens script.sh with editor nano)

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Java: Methoden

Machen es möglich, einmal geschriebenen Code mehrfach zu verwenden und ihn zu strukturieren.

GIT

Tool zur Versionierung, das kolaboratives Coding ermöglicht.

Links

• Java Standardbibliothek
• Java Scanner

Shortcuts (IntelliJ)

• Code automatisch formatieren: Opt + Cmd + L

• System.out.println: sout + Enter

• public static void main(String[] args): main oder psvm + Enter

• Cmd + D: Duplicate Codeline

• Shift + Opt + Arrow Up : Move Codeline

• Cmd + N: Generate Code

• Opt + Shift + 7 : Backslash

• Opt + Shift + 4 : Auswahlwerkzeug für Screenshot