Cpp中vector的输出打印

typedef vector<int> Vct;
Vct va;
va.push_back(1);
va.push_back(2);
va.push_back(3);

for(const int& k : va)
        cout << k << " ";
cout << endl;

template <class T>
void show(const T& x)
{
    cout << x << " ";
}

for_each(va.begin(),va.end(),show<int>);
    cout << endl;

#include <algorithm>
#include <iterator> // for ostream_iterator<>
copy(va.begin(),va.end(),ostream_iterator<int>(cout," "));
cout << endl;