✅ Overview:

• Similar to Python lists or NumPy arrays (dynamic, flexible).
• Elements stored in contiguous memory → efficient for push and pop at front/back.
• Operations take constant time regardless of queue size.

Declaration & Basic Operations

int j = 1,
    q2[$] = {3,4},        // Queue with 2 elements
    q[$]  = {0,2,3};      // Queue with 3 elements

initial begin
    q.insert(1, j);       // Insert j at index 1
    q.delete(1);          // Delete element at index 1

    q.push_front(6);      // Add element at front
    j = q.pop_back();     // Remove last element, assign to j
    q.push_back(8);       // Add element at end
    j = q.pop_front();    // Remove first element, assign to j

    foreach (q[i])
        $display(q[i]);   // Iterate over queue

    q.delete();           // Delete entire queue
end

Inserting queue inside a queue

int j=1,
    q2[$] = {3,4},
    q[$]  = {0,2,5};

initial begin
    q = {q[0], j, q[1:$]};         // Insert j after first element
    q = {q[0:2], q2, q[3:$]};     // Insert q2 after index 2
    q = {q[0], q[2:$]};           // Remove element at index 1

    q = {6, q};                   // Push at front
    j = q[$];                     // Access last element
    q = q[0:$-1];                 // Pop from back
    q = {q, 8};                   // Push at back

    j = q[0];                     // Access first element
    q = q[1:$];                   // Pop from front

    q = {};                       // Clear queue
end

Key Points:

• q[$] → last element
• q[0] → first element
• q[1:$] → slice from index 1 to end
• q.insert(index, value) / q.delete(index) → random access insert/delete
• Concatenation {} allows queue merging or element insertion anywhere.
• push_* / pop_* → efficient operations for front/back