Lua编程中如何实现队列?
在Lua中可以采用不同的方法来声明队列;最基本的一种是利用tables和repeat函数,取两个变量来帮助我们从队列中插入和删除元素。
示例
考虑下面显示的代码-
queue = {} queue.first = 0 queue.last = -1 queue.data = {} function insert(q, val) q.last =q.last+ 1 q.data[q.last] = val end function remove(q) if (q.first > q.last) then rval = -1 else print("remove: q.data[q.first]= ", q.data[q.first], " q.first= ", q.first) local rval = q.data[q.first] print("remove: rval= ", rval) q.data[q.first] = nil q.first=q.first+ 1 print("remove: q.first= ", q.first) end return rval end insert(queue,"a") insert(queue,"b") insert(queue,"c") for i,v in ipairs(queue.data) do print(i, v) end repeat local x = remove(queue) print("list item= ", x) until (queue.first > queue.last)输出结果
1 b 2 c remove: q.data[q.first]= a q.first= 0 remove: rval= a remove: q.first= 1 list item= nil remove: q.data[q.first]= b q.first= 1 remove: rval= b remove: q.first= 2 list item= nil remove: q.data[q.first]= c q.first= 2 remove: rval= c remove: q.first= 3 list item= nil