&和&&
In common:
& && and are represented: both ends of the symbol must be true at the same time, the final result will be true; wherein one end is false, then the final result is false
the difference:
&: The left is false, but also need to continue to determine the true and false at the right end
&&: left false, true and false judgments is not required right, i.e., no further operation right
| And ||
In common:
| And || have said: both ends of the symbols in one end is true, the final result is true; both ends are false, the final result is false
the difference:
|: Left whether true or false (even if true), but also the right to continue operations
||: true left and right ends no further operation, the result is true directly
to sum up
& And &&, | || run and the final result is the same
&& and || a little more efficient, to reduce unnecessary operations