如何使用按位＆（和）来实现这个？
这个问题在这里已经有了答案：
测试位标志的典型模式是
// Entire key match
if (returned_value & value_to_test == value_to_test) {
...
}
// Partial key match
if (returned_value & value_to_test != 0) {
...
}
例如，如果你想测试3号口袋是否满了：
if (returned_value & POCKET.P3_FULL == POCKET.P3_FULL) {
...
}
您可以通过|组合标志 并测试这种组合标志的部分匹配：
const int ALL_ARE_FULL = POCKET.P1_FULL | POCKET.P2_FULL | POCKET.P3_FULL;
...
// Test if any part of the flag is match (i.e. any pocket - at least one - is full)
// Please, notice != 0 comparison
if (returned_value & ALL_ARE_FULL != 0) {
...
}
// Compare with this: all three pockets are full
if (returned_value & ALL_ARE_FULL == ALL_ARE_FULL) {
...
}