LeetCode 简单操作 | 8. String to Integer (atoi)

/*
 * Leetcode8. String to Integer (atoi)
 * Funtion:Implement atoi to convert a string to an integer.
 * Example:
 * Author: LKJ
 * Date: 2017/3/01
 * Hint:
*/
#include <iostream>
#include <vector>
#include <string>
#include <cmath>
#include <algorithm>

using namespace std;

class Solution {
public:
    int myAtoi(string str) {
        int res = 0, sign = 1, i = 0;
        while(str[i] == ' '){i++;}
        if(str[i]=='-' || str[i]=='+'){
            sign = 1 - 2*(str[i++]=='-');
        }
        while((str[i]>='0')&&(str[i]<='9')){
            if((res>2147483647/10)||((res==214748364)&&((str[i]-'0')>7))){
                if(sign==1) return 2147483647;
                else return -2147483648;
            }
            res = res*10 + (str[i++]-'0');
        }
        return sign*res;
    }
};



int main(){
    string myin = "2147483648";
    int myout;
    Solution SA;

    myout = SA.myAtoi(myin);
    cout << myout << endl;

    return 0;
}