.. highlight:: go

types3.go
=========

::

    // types3.go

    package main

    import (
        "fmt"
    )

    type Point struct {
        x, y float64
    }

    // interace{} has no required methods, and so all types implement it
    func myPrint(arg interface{}) {
        // example of a type switch
        switch v := arg.(type) {
        case int:
            fmt.Printf("int=%v", v)
        case float32, float64:
            fmt.Printf("float=%v", v)
        case string:
            fmt.Printf("\"%v\"", v)
        case Point:
            fmt.Printf("(%v, %v)", v.x, v.y)
        default:
            fmt.Printf("???")
        } // switch
    } // myPrint

    func myPrintln(arg interface{}) {
        myPrint(arg)
        fmt.Println()
    } // myPrint

    func main() {
        myPrintln("cow")
        myPrintln(3.141)
        myPrintln(3141)
        myPrintln(Point{8, 2})
        myPrintln(true)

        var x interface{} = 5
        myPrintln(x)
        // the following lines won't compile due to a type error
        // y := x + 1
        // myPrintln(y)

        ix := x.(int) // type assertion
        y := ix + 1
        myPrintln(y)
    } // main