Computational Expression Computer and Java Basics Janyl Jumadinova - - PowerPoint PPT Presentation

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Computational Expression Computer and Java Basics Janyl Jumadinova - - PowerPoint PPT Presentation

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Computational Expression Computer and Java Basics Janyl Jumadinova 4 September, 2019 Janyl Jumadinova Computational Expression 4 September, 2019 1 / 22 What is Computer Science? A computation is a sequence of well-defined operations that

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Computational Expression

Computer and Java Basics Janyl Jumadinova 4 September, 2019

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What is Computer Science?

A computation is a sequence of well-defined operations that lead from an initial starting point to a desired final outcome

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What is Computer Science?

A computation is a sequence of well-defined operations that lead from an initial starting point to a desired final outcome

Computer science is the study of computation.

Computers are a medium for expression in computer science.

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What is a computer?

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Digital Computers

Information is broken into discrete pieces. Each piece is represented as a number, a binary number.

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Digital Computers

Information is broken into discrete pieces. Each piece is represented as a number, a binary number. Binary Numbers: Base 2 system. A single bit: either 0 or 1

  • can represent two items, e.g. state of the light bulb.

N bits can represent 2N unique items.

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What is a computer?

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What is a computer?

Slow deployment times Huge costs Wasted resources Difficult to scale Difficult to migrate

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IT Landscape is Changing

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IT Landscape is Changing

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Container-based Approach

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Container-based Approach

Containers are an app level construct

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Docker

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Docker

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Now the Bad News

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Now the Bad News

In this class you will not learn how to make Docker images, containers, etc. - you are only using Docker to run your programs.

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Now the Bad News

In this class you will not learn how to make Docker images, containers, etc. - you are only using Docker to run your programs. More bad news! Docker does not support Windows Home very well.

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Now the Bad News

In this class you will not learn how to make Docker images, containers, etc. - you are only using Docker to run your programs. More bad news! Docker does not support Windows Home very well. Plan for Windows Home: install software (below) directly on the machine - not use Docker.

  • Will do this in the lab tomorrow, in addition to learning how to use Git.

Mac, Windows Pro/Enterprise will still use Docker Desktop - no need to install anything else.

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Now the Bad News

In this class you will not learn how to make Docker images, containers, etc. - you are only using Docker to run your programs. More bad news! Docker does not support Windows Home very well. Plan for Windows Home: install software (below) directly on the machine - not use Docker.

  • Will do this in the lab tomorrow, in addition to learning how to use Git.

Mac, Windows Pro/Enterprise will still use Docker Desktop - no need to install anything else. Now we begin our adventure into programming!

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What is Computer Programming?

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What is Computer Programming?

Programming is the act of writing usable and useful software A program is a set of instructions

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Programming Language

We will use Java programming language in this class Java is a programming language originally developed by Sun Microsystems and released in 1995 as a core component of Sun’s Java platform

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HISTORY OF JAVA

Started development in 1991 at Sun Originally called Oak Intended for smart consumer-electronic devices Derives much syntax/concepts from C++ BCPL → B → C → C++ → Java Development almost halted, but 1993 saw introduction of web; Java was revamped to be able to easily add dynamic content to web pages Formally announced and released in May 1995 Released under GPL to the public in May 2007

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Programming in Java

Java is an object-oriented programming language

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Programming in Java

Java is an object-oriented programming language Objects are fundamental elements that make up a program

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Programming in Java

Java is an object-oriented programming language Objects are fundamental elements that make up a program Java has a library of software, called Java API, that is available for your use

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Java program development process

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Simple first Java Program: “Hello World”

/** This is the first program people write in a new language, the "Hello World!". In Java, this file must be named Welcome.java, with the first part of the name, Welcome, being the same as the name of the class. The filename itself (not the class name) must always end in .java to indicate to the operating system that it’s a java source file. */ public class Welcome { public static void main ( String args[] ) { System.out.println ( "Hello World!" ); } }

For today, try running this on https://www.jdoodle.com/online-java-compiler/

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Comments

Comments in Java can be one of three styles: Single line: starts at // anywhere on a line, ends at the end of that line Multi-line: starts with character sequence /* anywhere, ends with character sequence */ anywhere after that can span multiple lines javadoc: starts with character sequence /** anywhere, ends with character sequence */ anywhere, after that uses javadoc utility to create HTML documentation from code

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public class Welcome:

public means that something is available across packages (reserved word) Name of the class has to be the same as the name of the .java file

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public class Welcome:

public means that something is available across packages (reserved word) Name of the class has to be the same as the name of the .java file

public static void main ( String identifier[] ):

The particular form of main is required by Java. JVM starts executing here! main is a static method, it is part of its class and not part of objects. Strings in Java are sequence of characters

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public class Welcome:

public means that something is available across packages (reserved word) Name of the class has to be the same as the name of the .java file

public static void main ( String identifier[] ):

The particular form of main is required by Java. JVM starts executing here! main is a static method, it is part of its class and not part of objects. Strings in Java are sequence of characters

Braces { } are used to collect statements into a ”block”

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public class Welcome:

public means that something is available across packages (reserved word) Name of the class has to be the same as the name of the .java file

public static void main ( String identifier[] ):

The particular form of main is required by Java. JVM starts executing here! main is a static method, it is part of its class and not part of objects. Strings in Java are sequence of characters

Braces { } are used to collect statements into a ”block” Statements in Java end with semicolons.

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Printing

println: New line after printing print: No new line printf: Can specify format - may learn this later

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Character Strings

string literal in class String “ABC” “This is interesting” “ ” “91”

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Character Strings

string literal in class String “ABC” “This is interesting” “ ” “91” Use print or println methods to print a character string to the terminal System.out.println(“CMPSC 111”); the string “CMPSC 111” is a parameter: data sent to a method

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