前些时候做过的一份面试试题[9]

                   char[] achar = new char[ilength];

                   for(int i = 0; i < ilength; i++)

                            achar[i] = ssource[i];//直接可字串中的单个字符，关键在这儿了

                   string sleftpart = new string(achar);//直接构造回一个string

                   return sleftpart;

         } 

}