"Algorithm" string to int

"Algorithm" string to int

Encountered an interview problem, at that time only wrote a train of thought, now give concrete realization, is a kind of more stupid realization Way

     Public classStringtoint {/// <summary>        ///implement string conversion to int yourself/// </summary>        /// <param name= "str" ></param>        /// <returns></returns>         Public Static intToInt (stringstr) {            if(string. Isnullorwhitespace (str))//empty string directly returns 0            {                return 0; }            BOOLIsminus =false;//whether it is a negative number            intresult =0;//return Results             for(inti =0; I < Str. Length; i++)            {                intnum =ToInt (Str[i]); if(num = =-1)//not a number .                {                    return 0; }                if(num = =-2)//a negative case                {                    if(i = =0)//Yes, negative .{Isminus=true; }                    Else //negative sign in middle of string                    {                        return 0; }                }                checked //Check Arithmetic overflow{result+ = Totens (num, str. Length-i-1); }            }            returnIsminus?0-Result:result; }        /// <summary>        ///Convert char to int, note-(negative), cannot turn return-1, negative number returns-2/// </summary>        /// <param name= "C" ></param>        /// <returns></returns>        Private Static intToInt (Charc) {Switch(c) { Case '1':                    return 1;  Case '2':                    return 2;  Case '3':                    return 3;  Case '4':                    return 4;  Case '5':                    return 5;  Case '6':                    return 6;  Case '7':                    return 7;  Case '8':                    return 8;  Case '9':                    return 9;  Case '0':                    return 0;  Case '-':                    return-2; }            return-1; }        /// <summary>        ///get the corresponding number based on the number of digits/// </summary>        /// <param name= "i" ></param>        /// <param name= "index" ></param>        /// <returns></returns>        Private Static intTotens (intIintindex) {            if(I <=0)            {                return 0; }             for(intj =0; J < Index; J + +) {i= i *Ten; }            returni; }    }

"Algorithm" string to int