LeetCode String To Integer

Description

Implement atoi to convert a string to an integer.

The original problem is here.

The original code is here.

My Solution

I solve this problem in C++, as below:

/*
*String To Integer
*Author: shuaijiang
*Email: zhaoshuaijiang8@gmail.com
*/
#include<iostream>
#include<string.h>
#include<stdlib.h>
using namespace std;

class Solution {
public:
    int myAtoi(string str) {
        double result = 0.0;
        int flag = 1, work = 0;
        int size = str.size(), i = 0;
        while(str[i] == ' ')
            i++;
        if(str[i] == '-'){
            i ++;
            flag = 0;
        }
        else if(str[i] == '+')
        {
            i++;
            flag = 1;
        }
        
        for(;i<size;i++){
            if(str[i]>='0' && str[i]<='9'){
                result = result * 10 + (str[i] - '0');
                work = 1;
            }
            else
                break;
        }
        if(work == 0)
            return 0;
        if(flag == 1 && result  >= INT_MAX)
            return INT_MAX;
        if(flag == 0 && result > INT_MAX)
            return INT_MIN;
        
        int myInt = (int) result;
        if(flag == 0)
            myInt = -1 * myInt;
        return myInt;
    }
};

Note

To solve the problem, first discards as many whitespace characters as necessary until the first non-whitespace character is found.

When occur additional characters after those that form the integral number, stop the function, and return the current result.

If no valid conversion could be performed, a zero value is returned. If the correct value is out of the range of representable values, INT_MAX (2147483647) or INT_MIN (-2147483648) is returned.