public member function

std::map::clear

<map>
void clear ( );
Clear content
All the elements in the container are dropped: their destructors are called, and then they are removed from the container, leaving it with a size of 0.

Parameters

none

Return value

none

Example

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// map::clear
#include <iostream>
#include <map>
using namespace std;

int main ()
{
  map<char,int> mymap;
  map<char,int>::iterator it;

  mymap['x']=100;
  mymap['y']=200;
  mymap['z']=300;

  cout << "mymap contains:\n";
  for ( it=mymap.begin() ; it != mymap.end(); it++ )
    cout << (*it).first << " => " << (*it).second << endl;

  mymap.clear();
  mymap['a']=1101;
  mymap['b']=2202;

  cout << "mymap contains:\n";
  for ( it=mymap.begin() ; it != mymap.end(); it++ )
    cout << (*it).first << " => " << (*it).second << endl;

  return 0;
}


Output:
mymap contains:
x => 100
y => 200
z => 300
mymap contains:
a => 1101
b => 2202

Complexity

Linear in size (destructors).

See also

map::erase
Erase elements (public member function)
map::size
Return container size (public member function)
map::empty
Test whether container is empty (public member function)