Numbers
Store numbers and add them together.
1package main
2
3import "fmt"
4
5func main() {
6 apples := 3
7 bananas := 5
8 fmt.Println(apples + bananas)
9}
$ go run main.go
8
Every line, explained
package main- Every Go file starts by saying which package it belongs to. package main means "this is a program you can run", and Go will look inside it for func main.
import "fmt"- import brings in a package from Go's standard library. "fmt" (short for format) is the one full of printing tools, like fmt.Println.
func main() {- func main() { ... } is where a Go program starts. When you run the program, Go finds func main inside package main and runs everything between its braces, top to bottom.
apples := 3- := is Go's declare-and-assign: it creates a new variable AND stores a value in one step, and Go works out the type by itself. You will use := constantly in Go. (No semicolon needed; Go adds them for you behind the scenes.) Numbers don't need quotes: Go sees 3 and makes apples an int (a whole number).
bananas := 5- := is Go's declare-and-assign: it creates a new variable AND stores a value in one step, and Go works out the type by itself. You will use := constantly in Go. (No semicolon needed; Go adds them for you behind the scenes.)
fmt.Println(apples + bananas)- fmt.Println(...) prints what is inside the brackets to the terminal, then moves to a new line (Println is short for "print line"). The capital P matters: in Go, the tools a package shares all start with a capital letter. Go works out apples + bananas first (3 + 5 = 8), then prints the answer.
}- This closing brace } ends func main.