vector::begin
Returns a random-access iterator to the first element in the vector.
Syntax
const_iterator begin() const;
iterator begin();
Return Value
A random-access iterator addressing the first element in the vector or to the location succeeding an empty vector. You should always compare the value returned with vector::end to ensure it is valid.
Remarks
If the return value of begin is assigned to a vector::const_iterator, the vector object cannot be modified. If the return value of begin is assigned to an vector::iterator, the vector object can be modified.
Example
// vector_begin.cpp
// compile with: /EHsc
#include <vector>
#include <iostream>
int main()
{
using namespace std;
vector<int> c1;
vector<int>::iterator c1_Iter;
vector<int>::const_iterator c1_cIter;
c1.push_back(1);
c1.push_back(2);
cout << "The vector c1 contains elements:";
c1_Iter = c1.begin();
for (; c1_Iter != c1.end(); c1_Iter++)
{
cout << " " << *c1_Iter;
}
cout << endl;
cout << "The vector c1 now contains elements:";
c1_Iter = c1.begin();
*c1_Iter = 20;
for (; c1_Iter != c1.end(); c1_Iter++)
{
cout << " " << *c1_Iter;
}
cout << endl;
// The following line would be an error because iterator is const
// *c1_cIter = 200;
}
The vector c1 contains elements: 1 2 The vector c1 now contains elements: 20 2
Requirements
Header: <vector>
Namespace: std