Leetcode-8(Java) String to Integer (atoi)

標籤：

Implement atoi to convert a string to an integer.

Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input cases.

Notes: It is intended for this problem to be specified vaguely (ie, no given input specs). You are responsible to gather all the input requirements up front.

 

傳送門：https://leetcode.com/problems/string-to-integer-atoi/

把字串轉換成整型，注意空格和符號即可。

public class Solution {    public int myAtoi(String str)    {        if(str == null)            return 0;        str = str.trim();//去掉字串前面的空格        int len = str.length();        if(len == 0)            return 0;        char signal = ‘+‘;        double res = 0;        for(int i = 0; i < str.length(); i++)        {            char ch = str.charAt(i);            if(ch == ‘-‘ || ch == ‘+‘)            {                if(i != 0)                    return 0;                else                {                    if(ch == ‘-‘)                        signal = ‘-‘;                }            }            else if(ch >= ‘0‘ && ch <= ‘9‘)            {                res = res * 10 + ch - ‘0‘;            }            else                break;        }        if(signal == ‘-‘)            res = -res;        if(res > Integer.MAX_VALUE)            return Integer.MAX_VALUE;        else if(res < Integer.MIN_VALUE)            return Integer.MIN_VALUE;        else            return (int)res;    }    }

 

Leetcode-8(Java) String to Integer (atoi)