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go/doc/progs/json2.go
Shenghou Ma 5b7562dd6f doc/progs: use test/run.go for testing on Windows
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R=golang-dev, alex.brainman, rsc
CC=golang-dev
https://golang.org/cl/6218048
2012-09-03 03:49:03 +08:00

45 lines
707 B
Go

// cmpout
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"fmt"
"math"
)
func InterfaceExample() {
var i interface{}
i = "a string"
i = 2011
i = 2.777
// STOP OMIT
r := i.(float64)
fmt.Println("the circle's area", math.Pi*r*r)
// STOP OMIT
switch v := i.(type) {
case int:
fmt.Println("twice i is", v*2)
case float64:
fmt.Println("the reciprocal of i is", 1/v)
case string:
h := len(v) / 2
fmt.Println("i swapped by halves is", v[h:]+v[:h])
default:
// i isn't one of the types above
}
// STOP OMIT
}
func main() {
InterfaceExample()
}