Difference between revisions of "cpp/container/vector/clear"

Revision as of 16:48, 2 November 2012

Erases all elements from the container. After this call, size() returns zero.

Invalidates any references, pointers, and iterators referring to contained elements. Any past-the-end iterators are also invalidated.

Leaves the capacity() of the vector unchanged (Note: the standard's restriction on the changes to capacity is in the specification of reserve(), see SO).

Parameters

(none)

Return value

(none)

Complexity

Linear in the size of the container, i.e., the number of elements.

Example

#include <iostream>
#include <string_view>
#include <vector>
 
void print_info(std::string_view rem, const std::vector<int>& v)
{
    std::cout << rem << "{ ";
    for (const auto& value : v)
        std::cout << value << ' ';
    std::cout << "}\n";
    std::cout << "Size=" << v.size() << ", Capacity=" << v.capacity() << '\n';
}
 
int main()
{
    std::vector<int> container{1, 2, 3};
    print_info("Before clear: ", container);
    container.clear();
    print_info("After clear: ", container);
}

Before clear: { 1 2 3 }
Size=3, Capacity=3
After clear: { }
Size=0, Capacity=3

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

See also