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C++ Map Library - empty() Function
Description
The C++ function std::multimap::empty() tests whether multimap is empty or not. Multimap of size zero is considered as empty.
Declaration
Following is the declaration for std::multimap::empty() function form std::map header.
C++98
bool empty() const;
C++11
bool empty() const noexcept;
Parameters
None
Return value
Returns true if multimap is empty otherwise false.
Exceptions
This member function never throws exception.
Time complexity
Constant i.e. O(1)
Example
The following example shows the usage of std::multimap::empty() function.
#include <iostream> #include <map> using namespace std; int main(void) { multimap<char, int> m; if (m.empty()) cout << "Multimap is empty." << endl; m.emplace_hint(m.begin(), 'a', 1); if (!m.empty()) cout << "Multimap is not empty." << endl; return 0; }
Let us compile and run the above program, this will produce the following result −
Multimap is empty. Multimap is not empty.
map.htm
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