C++

Reference

<map>

map

public member function
<map>

std::map::size

size_type size() const;
size_type size() const noexcept;
Return container size
Returns the number of elements in the map container.

Parameters

none

Return Value

The number of elements in the container.

Member type size_type is an unsigned integral type.

Example

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// map::size
#include <iostream>
#include <map>

int main ()
{
  std::map<char,int> mymap;
  mymap['a']=101;
  mymap['b']=202;
  mymap['c']=302;

  std::cout << "mymap.size() is " << mymap.size() << '\n';

  return 0;
}

Output:
mymap.size() is 3


Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No elements are accessed: concurrently accessing or modifying them is safe.

Exception safety

No-throw guarantee: this member function never throws exceptions.

See also

map::max_size
Return maximum size (public member function)
map::empty
Test whether container is empty (public member function)