queue

A queue is a first-in, first-out data structure. Items Pushed are inserted at the rear, or 'tail' of the queue. Items removed, or Popped are taken from the 'front' of the queue.

Members

int Count

Number of items inserted onto the queue.

bool Push[ѕtring]

True if the item was pushed successfully.

string Pop

False is returned if IsEmpty is true.

bool IsEmpty

True if Count = 0, False otherwise.

string Peek

False is returned if IsEmpty is true.

Notes

Note

• Pop decreases Count by 1 unless IsEmpty is true.
• Push increases Count by 1. IsEmpty will never be true after calling Push.
• Peek retrieves the oldest element Pushed onto the queue. Count is not modified by calling Peek.

Examples

Sub QueueTest
    /declare q queue

    /echo 'Starting Queue Test'
    /echo 'Queue is Empty: ${q.IsEmpty}'

    | Push entries on the queue and pop them off.
    | Note: entries are inserted (Pushed) in and removed
    | (Popped) in the same order. That is, Pushing A, B, C, D, E
    | and then Popping them will return A, B, C, D, E.
    /echo 'Pushing items onto the Queue.'

    /if (!${q.Push[A]}) {
        /echo 'Queue Push of A failed.'
    /endmacro
    }
    /if (!${q.Push[B]}) {
        /echo 'Queue Push of B failed.'
    /endmacro
    }
    /if (!${q.Push[C]}) {
        /echo 'Queue Push of C failed.'
    /endmacro
    }
    /if (!${q.Push[D]}) {
        /echo 'Queue Push of D failed.'
    /endmacro
    }
    /if (!${q.Push[E]}) {
        /echo 'Queue Push of E failed.'
    /endmacro
    }

    /declare count int
    /varset count ${q.Count}
    /if (${count} != 5) {
        /echo 'Queue count is: ${count} and should be 5.'
    /endmacro
    }

    /echo 'Queue is Empty: ${q.IsEmpty}'

    | Peek at the front item:
    /echo 'Front item is: ${q.Peek}'

    | Pop items off the queue.

    /echo 'Popping item off queue: ${q.Pop}'
    /echo 'Popping item off queue: ${q.Pop}'
    /echo 'Popping item off queue: ${q.Pop}'
    /echo 'Popping item off queue: ${q.Pop}'
    /echo 'Popping item off queue: ${q.Pop}'

    /echo 'Queue is Empty: ${q.IsEmpty}'
    /echo 'Ending Queue Test'

    /return

This datatype is added by MQ2Collections.