public class MatrixTool
    {
        public MatrixTool()
        {
        
        }

        public string[] convert(string s)
        {
            string[] returnValues;
            //开平方
            if (s.Length>50)
            {
                returnValues = new string[1]{"This input Length overflow."};
            }
            else
            {
                double d = System.Math.Sqrt((double)s.Length);
                double di = System.Math.Ceiling(d);
                if (d!=di)
                {
                    returnValues = new string[1]{"This input has "+s.Length.ToString()+" digits, and "+s.Length.ToString()+" is not a perfect square."};
                }
                else
                {
                    try
                    {
                        System.Convert.ToDouble(s);
                    }
                    catch
                    {
                        returnValues = new string[1]{"This input hasn't numbers."};
                        return returnValues;
                    }
                    int i = System.Convert.ToInt32(di);
                    int k=0;
                    //转换
                    returnValues = new string[i];
                    for (int j=0 ;j<i;j++)
                    {
                        returnValues[j] = s.Substring(k,i);
                        k = i*(j+1)-1;
                    }
                }
            }
            return returnValues;
        }
    
    }