package string;

/**
 * Created by gouthamvidyapradhan on 21/03/2017.
 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.
 */
public class StringToInteger
{
    /**
     * Main method
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception
    {
        System.out.println(new StringToInteger().myAtoi("    2147483649a sdfasdf"));
    }

    public int myAtoi(String str)
    {
        boolean isPositive = true;
        if(str == null || str.trim().isEmpty()) return 0;
        str = str.trim();
        if(str.charAt(0) == '+')
        {
            isPositive = true;
            str = str.substring(1, str.length());
        }
        else if(str.charAt(0) == '-')
        {
            isPositive = false;
            str = str.substring(1, str.length());
        }

        else if(str.charAt(0) > '9' || str.charAt(0) < '0')
            return 0;
        int i = 0;
        for(int l = str.length(); i < l; i ++)
        {
            if(str.charAt(i) > '9' || str.charAt(i) < '0')
                break;
        }
        str = str.substring(0, i);
        long num = 0;
        for(int j = 0, l = str.length(); j < l; j++)
        {
            int n = (str.charAt(j) - '0');
            num *= 10;
            num += n;
            if(isPositive)
            {
                if(num > Integer.MAX_VALUE) return Integer.MAX_VALUE;
            }
            else
            {
                if((num * -1) < Integer.MIN_VALUE) return Integer.MIN_VALUE;
            }
        }
        if(isPositive)
            return (int)num;
        else return (int)(num * -1);
    }


}