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std::basic_string<CharT,Traits,Allocator>::capacity

From cppreference.com
< cpp‎ | string‎ | basic string
 
 
 
std::basic_string
 
size_type capacity() const;
(until C++11)
size_type capacity() const noexcept;
(since C++11)
(until C++20)
constexpr size_type capacity() const noexcept;
(since C++20)

Returns the number of characters that the string has currently allocated space for.

Contents

[edit] Parameters

(none)

[edit] Return value

Capacity of the currently allocated storage, i.e. the storage available for storing elements.

[edit] Complexity

Constant

[edit] Notes

Memory locations obtained from the allocator but not available for storing any element are not counted in the allocated storage. Note that the null terminator is not an element of the basic_string.

[edit] Example

#include <iostream>
#include <string>
 
void show_capacity(std::string const& s)
{
    std::cout << "'" << s << "' has capacity " << s.capacity() << ".\n";
}
 
int main()
{
    std::string s{"Exemplar"};
    show_capacity(s);
 
    s += " is an example string.";
    show_capacity(s);
}

Possible output:

'Exemplar' has capacity 15.
'Exemplar is an example string.' has capacity 30.

[edit] See also

returns the number of characters
(public member function) [edit]
reserves storage
(public member function) [edit]