string str;
int num = 100;
str = Convert.ToString(num);
Console.WriteLine("str[0] = " + str[0]);
Console.WriteLine(str[0]* str[0]* str[0]);
Console.WriteLine("str[1] = " + str[1]);
Console.WriteLine(str[1] * str[1] * str[1]);
Console.WriteLine("str[2] = " + str[2]);
Console.WriteLine(str[2] * str[2] * str[2]);

运行结果：

按道理结果不应该是

1*1*1=1？

0*0*0=0？