C++ ofstream outfile; outfile.open ("tel.txt",ios::out|ios::ofstream outfile;outfile.open ("tel.txt",ios::out|ios::

C++ ofstream outfile; outfile.open ("tel.txt",ios::out|ios::ofstream outfile;outfile.open ("tel.txt",ios::out|ios::
C++ ofstream outfile; outfile.open ("tel.txt",ios::out|ios::
ofstream outfile;
outfile.open ("tel.txt",ios::out|ios::

C++ ofstream outfile; outfile.open ("tel.txt",ios::out|ios::ofstream outfile;outfile.open ("tel.txt",ios::out|ios::
ios::app
：
以追加的方式打开文件

ios::out
：
文件以输出方式打开（内存数据输出到文件）
参照http://wenku.baidu.com/view/40ba6e2ced630b1c59eeb556.html 可以自己去看下