📘 C# Blog Series – Blog 38 **“C# Collections Deep Dive — List, Dictionary, HashSet, Queue, Stack का सबसे Practical Use

📘 C# Blog Series – Blog 38

**“C# Collections Deep Dive — List, Dictionary, HashSet, Queue, Stack का सबसे Practical Use

(Real-Life Example: Connected Device List, IMEI Lookup Dictionary, Packet Queue)”**

C# में Collections आपके पूरे backend system की रीढ़ हैं।
GPS Server, Billing System, ERP, API—
हर जगह collections का heavy use होता है।

हम आज सीखेंगे सबसे ज़्यादा इस्तेमाल होने वाले Collections:
✔ List<T>
✔ Dictionary<TKey, TValue>
✔ HashSet<T>
✔ Queue<T>
✔ Stack<T>

और साथ में Real-Life GPS Server Examples भी।

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🟦 1. List<T> — Most Common Collection (Dynamic Array)

✔ Ordered
✔ Duplicate allowed
✔ Index based access
✔ Fast insert at tail

Example:

List<GPSDevice> devices = new();
devices.Add(new GPSDevice());

✔ Real GPS Example: Connected Devices List

List<GPSDevice> ConnectedDevices = new();

हर नया device connect होता है → Add
Disconnect → Remove

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🟢 2. Dictionary<TKey, TValue> — Fastest Lookup (Key-Value Store)

सबसे powerful collection GPS system के लिए।

✔ Key से value 0.00001 सेकंड में मिलती है
✔ Duplicate key नहीं
✔ Perfect for IMEI lookup

Example:

Dictionary<string, GPSDevice> devices = new();
devices["861128068064267"] = new GPSDevice();

✔ Real GPS Example: IMEI → Device Mapping

var device = devices[imei]; // fastest lookup

यह lookup List से 50-100x faster होता है।

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⭐ Dictionary is MUST for GPS Servers

क्योंकि हर packet में IMEI आता है →
उससे device ढूँढना ही सबसे ज्यादा operations होता है।

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🌟 3. HashSet<T> — Unique Items Store

✔ No duplicates
✔ Fast membership checks
✔ Perfect for storing unique IMEIs, IPs, device types

Example:

HashSet<string> imeiSet = new();
imeiSet.Add("861128068064267");
imeiSet.Add("861128068064267"); // ignored

✔ Real GPS Example: Duplicate Packets रोकना

if(lastPackets.Contains(packetId)) return;
lastPackets.Add(packetId);

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🟠 4. Queue<T> — FIFO (First In, First Out)

Perfect जब order maintain करना हो।

Example:

Queue<string> packets = new();
packets.Enqueue("pkt1");
packets.Enqueue("pkt2");

var p = packets.Dequeue(); // pkt1

✔ Real-Life GPS Example: Packet Processing Queue

Incoming packets fast आते हैं →
processor धीरे parse कर पाता है।

So architecture:

TCP Receive Thread → Queue → Parser Thread

Use:

packetQueue.Enqueue(packet);

Parser thread:

string pkt = packetQueue.Dequeue();

Server stable रहता है, कोई packet loss नहीं।

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🔵 5. Stack<T> — LIFO (Last In, First Out)

Example:

Stack<string> history = new();
history.Push("cmd1");
history.Push("cmd2");
history.Pop(); // cmd2

✔ Real GPS Example: Command History, Undo Processing

Commands भेजने का इतिहास:

Stack<string> cmdHistory = new();
cmdHistory.Push("SET_TIME");
cmdHistory.Push("RESTART");

Undo last command → Pop।

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🟣 6. Real-Life GPS Architecture — Collections Usage Map

Feature	Recommended Collection	क्यों?
Connected devices	List<GPSDevice> → या better → Dictionary	fast search needed
IMEI lookup	Dictionary<string, GPSDevice>	सबसे fast
Avoid duplicates	HashSet<string>	unique maintain
Packet buffering	Queue<string>	FIFO
Undo commands	Stack<string>	LIFO
Device logs	List<string>	ordered storage
Device groups	Dictionary<string, List<GPSDevice>>	mapping

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🔥 7. Most Powerful Combination (Production-Ready Design)

Dictionary<string, GPSDevice> Devices;
Queue<string> PacketQueue;
HashSet<string> ProcessedPacketIds;

This is industry-standard GPS backend pattern.

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🧠 8. When to use which? (Super Simple Guide)

• List<T> → कई items चाहिए, order चाहिए

• Dictionary → कुछ key के through fast value चाहिए

• HashSet → duplicates avoid करने हैं

• Queue → sequential processing

• Stack → सबसे last वाला item चाहिए

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🔚 Conclusion

C# Collections आपके system को बनाते हैं:

✔ Fast
✔ Efficient
✔ Scalable
✔ Memory optimized
✔ GPS server friendly
✔ Professional architecture

GPS systems में इनका सही इस्तेमाल आपके server को
super-stable और lightning-fast बनाता है।