C++ set cbegin() Function

C++ set cbegin() Function with tutorial for beginners and professionals with examples on constructor, destructor, operator=(), begin(), cbegin(), cend(), end(), crbegin(), empty(), max_size(), clear(), emplace_hint(), key_comp(), swap() etc.

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C++ set cbegin()

C++ set cbegin() function is used to return a constant iterator pointing to the first element of the set container.

Syntax

const_iterator cbegin() const noexcept;  //since C++ 11

A const_iterator is an iterator that points to constant content.

Parameter

None

Return value

It returns a const_iterator pointing to the first element of the set.

Complexity

Constant

Iterator validity

No changes.

Data Races

The container is accessed.

Concurrently accessing the elements of a set is safe.

Exception Safety

This member function never throws exception.

Example 1

Let's see the simple example for cbegin() function:

#include <iostream>
#include <set>

using namespace std;

int main ()
{
  set<string> myset= {"Java", "C++","SQL"};

  // show content:
  for (auto it = myset.cbegin(); it != myset.cend(); ++it)
    cout <<*it << '\n';
    
  return 0;
}

Output:

C++
Java
SQL

In the above example, cbegin() function is used to return a constant iterator pointing to the first element in the myset set.

Example 2

Let's see a simple example:

#include <set>  
#include <iostream>  
  
int main( )  
{  
   using namespace std;  
   set <int> s1;  
   set <int>::iterator s1_Iter;  
   set <int>::const_iterator s1_cIter;  
  
   s1.insert( 1 );  
   s1.insert( 2 );  
   s1.insert( 3 );  
  
   s1_Iter = s1.begin( );  
   cout << "The first element of s1 is " << *s1_Iter << endl;  
  
   s1_Iter = s1.begin( );  
   s1.erase( s1_Iter );  
  
   // The following 2 lines would err because the iterator is const  
   // s1_cIter = s1.begin( );  
   // s1.erase( s1_cIter );  
  
   s1_cIter = s1.begin( );  
   cout << "The first element of s1 is now " << *s1_cIter << endl;  
}

Output:

The first element of s1 is 1
The first element of s1 is now 2

Example 3

Let's see a simple example to iterate over the set using while loop:

#include <iostream>
#include <set>
#include <string>
int main()
{
    using namespace std;
 
      set<string> myset = {"Robin","Dolly", "John","Nikita"};

    set<string>::const_iterator it; // declare an iterator

    it = myset.cbegin(); // assign it to the start of the vector

    while (it != myset.cend()) // while it hasn't reach the end
    {
        cout << *it<< "\n"; 
    // print the value of the element it points to
        ++it; // and iterate to the next element
    }
    cout << endl;
}

Output:

Dolly
John
Nikita
Robin

In the above example, cbegin() function is used to return an iterator pointing to the first element in the myset set.

Example 4

Let's see another simple example:

#include <iostream>
#include <string>
#include <set>

using namespace std;

int main ()
{
  set<int> number = {400, 350, 465, 290, 410};

   cout << "Increasing order: " << '\n';
   cout<<"______________________\n";
   
  set<int>::const_iterator cit;
  for (cit=number.cbegin(); cit!=number.cend(); ++cit)
    cout << *cit<< '\n';

    auto low = number.cbegin();
    auto high = number.rbegin();
    
    cout << "\nSmallest Number is: "<< *low <<endl;
    cout<< "Biggest Number is: "<<*high <<endl;

  return 0;
  }

Output:

Increasing order: 
______________________
290
350
400
410
465
Smallest Number is: 290
Biggest Number is: 465

In the above example, cbegin() function is used to return an iterator pointing to the first element in the myset set.

Next TopicSet end() Function

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C++ set cbegin() Function

C++ set cbegin()

Syntax

Parameter

Return value

Complexity

Iterator validity

Data Races

Exception Safety

Example 1

Example 2

Example 3

Example 4

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