After following, you can keep track of his dynamic information in a timely manner
Courses in the relevant section：Variable references for PHP constants and variables
加上&（and 符后），把变量指向同一个存值空间了; 也就是不论$fo或$bar的值如何发生变化，$fo变$bar也变，$bar发生变化，$fo也会发生变化。
2018-05-270个赞
