Changing backup memory to C ++ vector

Question

I have a vector with 1000 "nodes"

 if(count + 1 > m_listItems.capacity())
     m_listItems.reserve(count + 100);

The problem is that I also clarify this when I am going to replenish it.

m_listItems.clear();

Capacity does not change. I used resizing (1); but this does not seem to change the possibility. So how to change the reserve?

Answer 1

vector<Item>(m_listItems).swap(m_listItems);

hiding again m_listItems: http://www.gotw.ca/gotw/054.htm (Herb Sutter)

If you still want to clear it, replace it with an empty vector:

vector<Item>().swap(m_listItems);

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Answer 2

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std::vector<foo> v(1000); // Create a vector with capacity for 1000 elements

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Edit:

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Answer 3

std::vector< int > v;
// ... fill v with stuff...
std::vector< int >().swap( v );

Answer 4

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vector< int > tmp;
old.swap( tmp );

Answer 5

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