when someone abandons you，it is him that gets loss because he lost someone who truly loves him but you just lost one who doesn’t love you.
问题描述：
./a.out 为什么一定要加 ./？
理由：
因为当前目录不在你的 PATH 路径中
linux 系统缺省的 PATH，是没有 ./ 的，不安全；
如果你想要，可以在 bashrc 加入
1 | export PATH=$PATH:./ |
either I will find a way, or I will make one.