c++ vector.clear()

void clear ( );

Clear content 清除全部的内容

All the elements of the vector are dropped: their destructors are called, and then they are removed from the vectorcontainer, leaving the container with a size of 0.

// clearing vectors
#include <iostream>
#include <vector>
using namespace std;

int main ()
{
  unsigned int i;
  vector<int> myvector;
  myvector.push_back (100);
  myvector.push_back (200);
  myvector.push_back (300);

  cout << "myvector contains:";
  for (i=0; i<myvector.size(); i++) cout << " " << myvector[i];

  myvector.clear();
  myvector.push_back (1101);
  myvector.push_back (2202);

  cout << "\nmyvector contains:";
  for (i=0; i<myvector.size(); i++) cout << " " << myvector[i];

  cout << endl;

  return 0;
}

myvector contains: 100 200 300
myvector contains: 1101 2202