The Go Programing Language, Three chapters of John Sonmez Course in PluralSight: 1-Go Overview, 2-Go Development, 3-Variables, Types, Pointers

1. The Go
Programming
Language
By İbrahim Kürce
Quoted from John Sonmez
Three chapters: Go Overview, Go Development and Variables, Types, Pointers

2. 1 – Go Overview – What is Go?
 Compiled
 Garbage-collected
 Concurrent

3. Compiled
 Code adapted to machine that they’re running on
 Compiled down to machine languages like C, C++
 More efficient and better performance than interpreted languages
 Supported operating systems: Linux, Mac OS
X, FreeBSD, OpenBSD, Plan 9, Windows
 Supported processors: i386, amd64, ARM

4. Garbage-collected
 You do not have to manage memory as programmer, unlike C, C++
 Runtime handles for you
 Garbage collection is very fast, latency free

5. Concurrent
 Concurrency is to do more than one thing at a time
 Programming languages like C++ and Java, concurrency is possible but hard to
manage. It is not part of language
 Go has built in concurrency support
 It is called Go Routines for concurrent functions

6. Go’s Origins
 Three Google engineers want a system level languages for aging systems level
languages
 Go was designed very fast compiling language
Sept 2007
Dream of Go
March 2012
Go 1
released
May 2010
Used
internally at
Google
Nov 2009
Officially
announced

7. What makes Go different?
 Efficient like a static language, ease of use like dynamic language
 Type-safe and memory-safe
 Latency free garbage collection
 Fast compile times
 It does not have assertions and method overloading

8. 2 – Go Development - Packages
 Way to modularize code
 Similar to namespaces
 Collection of types and functions
 Can import packages in your code
 Redistribute those packages
 A lot of built-in packages, https://golang.org/pkg/

9. Imports
Code.go
Source code
Local packages
Remote packages

10. Imports
 Go knows whether your code needs those packages
 Has ability to go out and get remote packages
 Your code could refer to github etc. repositories

11. Hello World
package main Required package name "main"
import "fmt" Package comes with Go
func main(){ Curly braces is near by function name
fmt.Println("Hello World")
}
Println start with upper case, cause it is exported method

12. Hello World
 Direct run, not generate .exe file
go run hello.go
 To Build to generate .exe file
go build hello.go
 To run after build
hello.exe

13. 3 – Variables, Types and Pointers
 Basic Types
 bool
 string
 int, int8, int16, int32, int64
 uint, uint8, uint16, uint32, uint64, uintptr
 byte(unit8)
 rune(int32), like a char
 float32, float64
 complex64, complex128

14. Types
 Other types
 Array
 Slice
 Struct
 Pointer
 Function
 Interface
 Map
 Channel

15. Basic Declaration

16. Multi-Declaration and Initialization

17. Multi-Declaration and Initialization
 Default value is 0 for int types
 Default value is always set in Go language
Without Types Without var

18. Multi-Declaration and Initialization
 Do not need to have same type in multi-declaration

19. Pointer Basics
 Pointer is a type of variable that is going to contain a memory address of another
variable
 string pointer has same type with string type
Hello
World
0xc042
00a270

20. Pointer Basics, Passing Things
 Pointer’s type is that type is going to refer to what type of variable
 We pass value in Go function, this value will be copied, inside function, we change
this value, originial value is not changed
function
43
43
function
43
45

21. Passing Things
 If we pass a pointer to function, pointer also will be copied but it points same
memory location. So if we change value inside function, originial value will also be
changed
function
43
0x0123
0x0123

22. Basic Pointer Example
 greeting is a pointer, if we write it directly, it shows memory address
 If we write *greeting, it shows Hello world

23. Pointer Assignment
 If we change value of pointer, we also change originial value

24. No Classes in Go
 Go is not object-oriented language
 Instead of using classes in Go, we use what’s called user define types
 For example;

25. Basic User Types
 Salutation struct definition

26. Constants
 In Go, you can define constants without defining the type
 PI is numeric, Language is string type
 A, B, C = 0, 1, 2 respectively

27. End of Go Overview, Go Development and
Variables, Types, Pointers