package main// 参考文档：//     https://github.com/Unknwon/the-way-to-go_ZH_CN/blob/master/eBook/05.2.mdimport (     "fmt"    "strconv")func main() {    var orig string = "ABC"    // var an int    var newS string    // var err error    fmt.Printf("The size of ints is: %d\n", strconv.IntSize)    // anInt, err = strconv.Atoi(origStr)    an, err := strconv.Atoi(orig)    if err != nil {        fmt.Printf("orig %s is not an integer - exiting with error\n", orig)        return    }    fmt.Printf("The integer is %d\n", an)    an = an + 5    newS = strconv.Itoa(an)    fmt.Printf("The new string is: %s\n", newS)}