C++ set cbegin() Function

by Online Tutorials Library July 22, 2022

C++ set cbegin()

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

Syntax

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

begin()beginners c cbegin()cend()clear()constructor cpp set crbegin()destructor emplace_hint()empty end()function introduction key_comp()max_size()operator professionals swap()tutorial

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

What is boot

C++ Math scalbln() Function

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