非分隔的ASCII（ASC）文件就是一个ASCII字符流；数据流中的行由行分隔符分隔，行中的每一列由起始位置和结束位置定义。
A non-delimited ASCII ( ASC ) file is a stream of ASCII characters ; rows in the data stream are separated by row delimiters , and each column within a row is defined by a beginning and ending location .
符行中