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The GoProgramming LanguageBy İbrahim Kürce
Quoted from John Sonmez
Three chapters: Go Overview, Go Development and Variables, Types, Pointers
1 – Go Overview – What is Go?
Compiled
Garbage-collected
Concurrent
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
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
Concurrent
Concurrency is to do more than one thing at a time
Programming languages like C++ and Java, concurrency is possible but hard tomanage. It is not part of language
Go has built in concurrency support
It is called Go Routines for concurrent functions
Go’s Origins
Three Google engineers want a system level languages for aging systems levellanguages
Go was designed very fast compiling language
Sept 2007Dream of Go
March 2012Go 1
released
May 2010Used
internally at Google
Nov 2009Officially
announced
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
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/
Imports
Code.go
Source code
Local packages
Remote packages
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
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
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
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
Types
Other types
Array
Slice
Struct
Pointer
Function
Interface
Map
Channel
Basic Declaration
Multi-Declaration and Initialization
Multi-Declaration and Initialization
Default value is 0 for int types
Default value is always set in Go language
Without Types Without var
Multi-Declaration and Initialization
Do not need to have same type in multi-declaration
Pointer Basics
Pointer is a type of variable that is going to contain a memory address of anothervariable
string pointer has same type with string type
HelloWorld
0xc04200a270
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 changethis value, originial value is not changed
function
4343
function
4345
Passing Things
If we pass a pointer to function, pointer also will be copied but it points samememory location. So if we change value inside function, originial value will also be changed
function
430x0123
0x0123
Basic Pointer Example
greeting is a pointer, if we write it directly, it shows memory address
If we write *greeting, it shows Hello world
Pointer Assignment
If we change value of pointer, we also change originial value
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;
Basic User Types
Salutation struct definition
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
End of Go Overview, Go Development andVariables, Types, Pointers
