C++ set - cbegin() Function

The C++ set::cbegin function returns the constant iterator (const_iterator) pointing to the first element of the set.

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 set element is not itself constant.

Note: Set is an ordered data container which implies all its elements are ordered all the time.

Syntax

C++11

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 set::cbegin function returns the const_iterator pointing to the first element of the set called MySet.

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

  cit = MySet.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 set called MySet contains integer values and set::cbegin function is used with set::cend function to specify a range including all elements of the set container. Please note that, Set is an ordered data container.

#include <iostream>
#include <set>
using namespace std;
 
int main (){
  set<int> MySet{55, 25, 128, 5, 72};
  set<int>::const_iterator cit;

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

  return 0;
}

The output of the above code will be:

5 25 55 72 128

❮ C++ <set> Library