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std::map::clear(3)	      C++ Standard Libary	    std::map::clear(3)

NAME
       std::map::clear - std::map::clear

Synopsis
	  void clear();		  (until C++11)
	  void clear() noexcept;  (since C++11)

	  Erases  all elements from the	container. After this call, size() re-
       turns zero.

	  Invalidates any references, pointers,	or iterators referring to con-
       tained elements.
	  Any past-the-end iterator remains valid.

Parameters
	  (none)

Return value
	  (none)

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

Example
       // Run this code

	#include <algorithm>
	#include <iostream>
	#include <map>

	int main()
	{
	    std::map<int, char>	container{{1, 'x'}, {2,	'y'}, {3, 'z'}};

	    auto print = [](std::pair<const int, char>&	n) {
		std::cout << " " << n.first << '(' << n.second << ')';
	    };

	    std::cout << "Before clear:";
	    std::for_each(container.begin(), container.end(), print);
	    std::cout << "\nSize=" << container.size() << '\n';

	    std::cout << "Clear\n";
	    container.clear();

	    std::cout << "After	clear:";
	    std::for_each(container.begin(), container.end(), print);
	    std::cout << "\nSize=" << container.size() << '\n';
	}

Output:
	Before clear: 1(x) 2(y)	3(z)
	Size=3
	Clear
	After clear:
	Size=0

See also
	  erase	erases elements
		(public	member function)

http://cppreference.com		  2022.07.31		    std::map::clear(3)

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