C++ Standard Library C++ STL Library

C++ <vector> - cbegin() Function



The C++ vector::cbegin function returns the constant iterator (const_iterator) pointing to the first element of the vector. Please note that, Unlike the vector::front function, which returns a direct reference to the first element, it returns the const_iterator pointing to the same element of the vector.

C++ cbegin cend

Note: A const_iterator is an iterator that points to constant value. The difference between iterator and const_iterator is that the const_iterator cannot be used to modify the content it points to, even if the vector element is not itself constant.

Syntax

const_iterator cbegin() const noexcept;

Parameters

No parameter is required.

Return Value

A const_iterator to the beginning of the sequence container.

Time Complexity

Constant i.e, Θ(1).

Example:

In the example below, the vector::cbegin function returns the const_iterator pointing to the first element of the vector called MyVector.

#include <iostream>
#include <vector>
using namespace std;
 
int main (){
  vector<string> MyVector{"Alpha","Coding","Skills"};
  vector<string>::const_iterator cit;

  cit = MyVector.cbegin();
  cout<<*cit<<" ";
  cit++;
  cout<<*cit<<" ";
  cit++;
  cout<<*cit<<" ";
  return 0;
}

The output of the above code will be:

Alpha Coding Skills

Example:

Lets see another example where the vector called MyVector contains integer values and vector::cbegin function is used with vector::cend function to specify a range including all elements of the vector container.

#include <iostream>
#include <vector>
using namespace std;
 
int main (){
  vector<int> MyVector{10, 20, 30, 40, 50};
  vector<int>::const_iterator cit;

  for(cit = MyVector.cbegin(); cit != MyVector.cend(); ++cit)
    cout<<*cit<<" ";

  return 0;
}

The output of the above code will be:

10 20 30 40 50 

❮ C++ <vector> Library

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