字符串转整型

func MyAtoi(s string) int {
	//fmt.Printf("input:%s\n", s)
	var arrString = []rune(s)
	lenArr := len(arrString)
	if lenArr == 0 {
		return 0
	}

	//查找第一个索引
	firstIndex := 0
	for j := 0; j < lenArr; j++ {
		if arrString[j] != 32 {
			break
		}
		firstIndex++
	}

	//fmt.Printf("firstIndex:%d\n", firstIndex)

	fuNum := false //是否含有符号
	firstChar := string(arrString[firstIndex])
	if firstChar == "-" {
		fuNum = true
	}
	if firstChar == "-" || firstChar == "+" {
		firstIndex++
	}

	//fmt.Printf("firstIndex:%d\n", firstIndex)

	var result int
	result = 0
	yuejie := false
	for i := firstIndex; i < lenArr; i++ {
		//fmt.Println(string(arrString[i]))
		if arrString[i] < 48 {
			//fmt.Println("aaa")
			break
		}
		if arrString[i] > 57 {
			//fmt.Println("bbb")
			break
		}

		result = result*10 + (int(arrString[i]) - 48)
		if result > math.MaxInt32 {
			result = math.MaxInt32
			yuejie = true
		}
	}

	if fuNum {
		if yuejie {
			result = 0 - result - 1
		} else {
			result = 0 - result
		}

	}

	//fmt.Printf("output:%d\n", result)
	return result
}