【面试题】反转整数

func Reverse(x int32) int32 {

    var xx, rx, tnum, pos, negative int32
    //备份原值
    xx = x

    var posNum, posStart, maxLan int
    //int32最大长度
    maxLan = 11

    //判断是否负数
    negative = 1
    if x < 0 {
        negative = -1
        xx = xx * -1
    }

    for i := maxLan; i >= 0; i-- {
        tnum = int32(math.Pow10(i))
        if xx >= tnum {
            pos = xx / tnum
            if pos > 0 || posStart > 0 {
                if posStart == 0 {
                    posStart = 1
                }

                fmt.Println(i, pos)

                posNum++
                rx += pos * (int32(math.Pow10(posNum - 1)))
            }
            xx = xx - pos*tnum
        }
    }
    rx = rx * negative
    return rx
}

你这写的有点复杂了，而且还有 bug：Reverse(10010) 结果是 11，明显不对！

有个简单粗暴的实现方法

package main

import (
    "log"
    "strconv"
)

func reverseInt(param int) int64 {
    var dataToReturn int64

    // 把被反转的参数转为字符串并填充到runes切片中
    runes := []rune(strconv.FormatInt(int64(param), 10))
    // 把runes切片的内容颠倒顺序
    for start, end := 0, len(runes)-1; start < end; start, end = start+1, end-1 {
        runes[start], runes[end] = runes[end], runes[start]
    }

    // 把字符串转为整数，负数特别对待
    if param < 0 {
        dataToReturn, _ = strconv.ParseInt(string(runes[:len(runes)-1]), 10, 64)
        dataToReturn = dataToReturn * int64(-1)
    } else {
        dataToReturn, _ = strconv.ParseInt(string(runes), 10, 64)
    }

    return dataToReturn
}

func main() {
    log.Println(reverseInt(-10010))
}