下列代码中“using namespace std;”为何意?
#include <iostream.h>
#include <deque>
using namespace std; //这行代码,缺了又不行!
int main()
{
deque<int> coll;
coll.push_front(1);
coll.push_front(2);
coll.push_front(10);
coll.push_front(5);
coll.push_front(4);
coll.push_front(8);
coll.push_back(11);
coll.push_back(15);
for(int i = 0; i < coll.size(); i ++)
{
cout << coll[i] << ' ';
}
cout << endl;
cout << coll.back() << endl;
return 1;
}