Numbers are passed by value

---

examples/function-increment/function_increment.go

package main

import "fmt"

func main() {
    a := 1
    fmt.Printf("before %v\n", a)
    inc(a)
    fmt.Printf("after %v\n", a)
}

func inc(val int) {
    fmt.Printf("val in inc: %v\n", val)
    val++
    fmt.Printf("val in inc: %v\n", val)
}

before 1
val in inc: 1
val in inc: 2
after 1