vector::begin
Returns a random-access iterator to the first element in the vector.
const_iterator begin() const;
iterator begin();
Return Value
A random-access iterator that points to the first element, 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>
using namespace std;
int main()
{
vector<int> vec;
vector<int>::iterator pos;
vector<int>::const_iterator cpos;
vec.push_back(1);
vec.push_back(2);
cout << "The vector vec contains elements:";
for (pos = vec.begin(); pos != vec.end(); ++pos)
{
cout << " " << *pos;
}
cout << endl;
cout << "The vector vec now contains elements:";
pos = vec.begin();
*pos = 20;
for (; pos != vec.end(); ++pos)
{
cout << " " << *pos;
}
cout << endl;
// The following line would be an error because iterator is const
// *cpos = 200;}
The vector vec contains elements: 1 2 The vector vec now contains elements: 20 2
Requirements
Header: <vector>
Namespace: std