C++ vector or Queue to build large Q in term of memory and speed

Question

I am building a large queue of messages and using only PUSH and POP so which will be more efficient (vector or Queue) to maintain a large data with maximum speed

struct MQStruct {
    wchar_t *serviceName; 
    int durability; 
    int msgType; 
    int msgHeader; 
    wchar_t *msgId; 
    wchar_t *payload; 
    int payloadSize; 
    int ttl; 
    int priority;
}MQStructObj;

vector<MQStruct> MQvector;
queue<MQStruct> MSQ;

int SendMessage(wchar_t *serviceName, int durability, int msgType, int msgHeader, wchar_t *msgId, wchar_t *payload, int payloadSize, int ttl, int priority) {

MQStructObj.serviceName=serviceName;
MQStructObj.durability=durability;
MQStructObj.msgType=msgType;
MQStructObj.msgHeader=msgHeader;
MQStructObj.msgId=msgId;
MQStructObj.payload=payload;
MQStructObj.payloadSize=payloadSize;
MQStructObj.ttl=ttl;
MQStructObj.priority=priority;

    //Which one is better (Vector or Queue) in term of memory, speed and why

MSQ.push(MQStructObj);

    //OR

MQvector.push_back(MQStructObj);


return 0;
}

Solution 1

With std::vector you can not efficiently simulate a queue - you may only PUSH and POP from one side of the container. If you need to implement a message queue then use a queue, that's what it's meant for.

Solution 2

There are many discussions regarding queue/vector/list on SO, you could search and reuse the resource. In short:

• Use std::queue: If you need fast insertion and deletion at both its beginning and its end;
• Use std::vector, if you need random access to elements
• When there are frequent insertions and deletions from the middle of the sequence you need std::list

As you use only push/pop to the container, std::queue is the way instead of std::vector for sure.

You can get more details from: http://en.cppreference.com/w/cpp/container

Comments

[Gorpik]

In fact, std::queue (which uses an std::deque by default) is even better because it offers a more natural interface for OP's purposes and should have no performance penalty against a direct std::deque.

[Shahzad]

Thank you so much for detail explanation, I don't need insertion and deletion on both ends so with ref to your ans, std::queue is better choice for me

[billz]

@Shahzad right. use std::queue instead, I'v updated my answer accordingly