CODEWITHSUNDEEP
c++vector
xarzu
xarzu

Reputation: 9479

how do I remove a node from a vector in C++

How do I remove a node from a vector in C++ This code does not even compile

typedef vector<simple_node> container;
//======================================
// remove an item from the queue that matches what we arelady have
container parser::removeFromQueue(container local_container, simple_node *node_to_remove)
{
    for (auto i = local_container.begin(); i != local_container.end(); i++)
    {
        if ((i->toy == node_to_remove->toy) &&
            (i->type == node_to_remove->type))
            {
                local_container.erase(remove(local_container.begin(), local_container.end(), i), local_container.end());
                break;
            }
    }
    return local_container;

}

It fails on the line

local_container.erase(remove(local_container.begin(), local_container.end(), i), local_container.end());

The compiler complains about an inquality assignment.

Upvotes: 1

Views: 162

Answers (1)

Blastfurnace
Blastfurnace

Reputation: 18652

I think you're doing this the hard way. Instead of a hand-written loop to iterate over the container you can use std::remove_if from the standard library with a lambda expression.

container parser::removeFromQueue(container local_container, simple_node *node_to_remove)
{
    auto pred = [node_to_remove](const simple_node &node) {
        return node.toy == node_to_remove->toy && node.type == node_to_remove->type;
    };
    local_container.erase(std::remove_if(local_container.begin(), local_container.end(), pred), local_container.end());
    return local_container;
}

The above function will remove all elements that meet the condition. If you only want to remove the first matching element it's a simple change.

container parser::removeFromQueue(container local_container, simple_node *node_to_remove)
{
    auto pred = [node_to_remove](const simple_node &node) {
        return node.toy == node_to_remove->toy && node.type == node_to_remove->type;
    };
    auto itr = std::find_if(local_container.begin(), local_container.end(), pred);
    if (itr != local_container.end()) {
        local_container.erase(itr);
    }
    return local_container;
}

Upvotes: 3

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