Basic GoLang control flow

golang-control-flow.go

package main

import (
    "fmt"
    "strconv"
)

func main(){
    var x int           // Declare variable

    fmt.Scanf("%d",&x)  // Input

    if x<5 {            // If
        fmt.Println("told ya")
    } else if x>10 {            // Else must be in the same line as ending '}'
        fmt.Println("no way")
    } else {
        fmt.Println("he he")
    }

    if y := expensiveComputation(x); y>10 {     // First assignment, then check
        fmt.Println("no way at Y")
    }

    switch x%3 {
        case 0:
            fmt.Println("Good")
        case 1:
            fmt.Println("Better")
        case 2:
            fmt.Println("Best")
            fallthrough         // Falls through to next case
        default:
            fmt.Println("Never say never")
    }

    for i:=0; i<x; i++ {        // Simple For Loop [ Only loop in GoLang ]
        fmt.Print("Iteration ", i, ", ")     // Multivalue print
    }

    for key, value := range map[string]int{"one": 1, "two": 2, "three": 3} {
        // for each pair in the map, print key and value
        fmt.Printf("key=%s, value=%d\n", key, value)
    }

    fmt.Println( do(21) )
    fmt.Println( do("bitrab") )
    fmt.Println( do(3.142) )
}

func expensiveComputation(x int)(y int){
    return x+2
}

func do(v interface{}) string {
    switch u := v.(type) {
    case int:
        return strconv.Itoa(u*2) // u has type int
    case string:
        mid := len(u) / 2 // split - u has type string
        return u[mid:] + u[:mid] // join
    }
    return "unknown"
}