Vector Type

A vector is a collection of objects of a single type, each of which has an associated integer index. As with strings, the library takes care of managing the memory associated with storing the elements. We speak of a vector as a container because it contains other objects. All of the objects in a container must have the same type.
 
To use a vector, we must include the appropriate header. In our examples, we also assume an appropriate using declaration is made.
Cosnider the following example for vectors working :

Example

// constructing vectors
#include <iostream>
#include <vector>

using namespace std;
int main() 
{
	unsigned int i;

	// constructors used in the same order as described above:
	vector<int> first; // empty vector of ints
	vector<int> second(4, 100); // four ints with value 100
	vector<int> third(second.begin(), second.end()); // iterating through second
	vector<int> fourth(third); // a copy of third

	// the iterator constructor can also be used to construct from arrays:
	int myints[] = { 16, 2, 77, 29 };
	vector<int> fifth(myints, myints + sizeof(myints) / sizeof(int));

	cout << "The contents of fifth are:";
	for (vector<int>::iterator it = fifth.begin(); it != fifth.end(); ++it)
		cout << ' ' << *it;
	cout << '\n';
	
	getchar();

	return 0;
}

Output

The contents of fifth are: 16 2 77 29