Go

Go is a compiled, statically typed programming language developed by Google.

// hello beer: drink 0.5 liter in 4 rounds
package main

import (
    "fmt"
    "time"
)

const LITER_PER_SIP = 37e-3

func sips2liter( num_sips int ) float64 {
    return float64( num_sips ) * LITER_PER_SIP
}

func main(){

    beer_l := 0.5
    rounds := 4
    sips_per_round := [] int {3, 7, 4, 2}

    fmt.Printf("I drink %g l in %d rounds:\n", beer_l, rounds)
    for _, sips := range sips_per_round {
        fmt.Printf("I drink %d sips.\n", sips)
        time.Sleep( time.Duration(sips) * time.Second)
        beer_l = beer_l - sips2liter( sips )
        if (beer_l <= 0.0){
            fmt.Println("My beer is empty!")
            break
        } else {
            fmt.Printf("I have %g l beer left.\n", beer_l)
        }
    }
}

Run your own program at the Go Playground!

Important Basics

• every code file starts with the package statement
• program entry is function main in package "main".
• types can be implicit x := "hello" or explicit var x string = "hello"
• Go distinguishes between small and capital words
• files must end with a blank line
• Go supports complex numbers: var z complex = 5 + 3i
• concurrent tasks are created with go test()
• omits some common features such as inheritance, generics, assertions, pointer arithmetic, and implicit type conversions.

Data Types

In Go you can define distinct new types such as type ipv4addr uint32

• Integers: int,uint, int8, int16, int32, int64, uint8, uint16, uint32, uint64
• Floats: float32, float64, complex64, complex128
• Others: byte, bool, string

Collections

• Arrays: var a [10]int, Length via len(a)
• Slices: p := []int{2, 3, 5, 7, 11, 13}
• Maps: map[string]int{"Alice": 2, "Bob": 13}

Control Flow

if answer != 42 {
    return "Wrong answer"
}

switch score {
    case 0, 1, 3:
        fmt.Println("Terrible")
    case 4, 5:
        fmt.Println("Awesome")
    default:
        fmt.Println("Unknown")
}

Example: Hello World

package main

import "fmt"

func main() {
    fmt.Println("Hello, World")
}

References

• Go-lang