Writing custom atoi() function

Question

I am trying to write a c code that mulplies two numbers and I wrote a custom atoi() function to convert char to int. I tried running the exe file with the following arguments ./exe 2 3 but it giving me a result of 0 instead of 6 and I can't seem to find where the bug in my code is coming from. here is a snippet of me code

 int myatoi(char* str)
{
        int i = 0, result = 0, sign = 1, flag;
/** Chheck for whitespce*/
        while (str[i] == ' ')
                i++;
/**Check for sign of the first num*/
        if (str[i] == '-')
        {
                sign = -1;
                i++;
        }
        for (; str[i] !='\0'; i++)
        {
                if (str[i] >= '0' && str[i] <= '9')
                {
                        result = result * 10 + (str[i] - '0');
                        flag = 1;
                        if (str[i + 1] < '0' || str[i + 1] > '9')
                        {
                                flag = 0;
                                break;
                        }
                }
        }

        if (flag == 0)
                return (0);
        return (sign * result);
}

int main(int argc, char *argv[])
{
        int i, result = 1;

        if (argc < 2)
        {
                printf("Error\n");
                return (1);
        }
        for (i = 1; i  < argc; i++)
        {
                result = result * myatoi(argv[i]);
        }
        printf("%d\n", result);

        return (0);
}