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C++ multiset begin()C++ multiset begin() function is used to return an iterator referring to the first element of the multiset container. Syntaxiterator begin(); //until C++ 11 const_iterator begin() const; //until C++ 11 iterator begin() noexcept; //since C++ 11 const_iterator begin() const noexcept; //since C++ 11 ParameterNone Return valueIt returns an iterator pointing to the first element of the multiset. ComplexityConstant. Iterator validityNo changes. Data RacesThe container is accessed. Neither the constant nor the non-constant versions modify the container. Exception SafetyThis function never throws exceptions. Example 1Let's see the simple example for begin() function: #include <iostream> #include <set> using namespace std; int main () { multiset<string> mymultiset= {"Java", "C++", "SQL","C++"}; // show content: cout<<"Contents of mymultiset are: "<<endl; for (multiset<string>::iterator it=mymultiset.begin(); it!=mymultiset.end(); ++it) cout << *it<< '\n'; return 0; } Output: Contents of mymultiset are: C++ C++ Java SQL In the above example, begin() function is used to return an iterator pointing to the first element in the mymultiset multiset. Example 2Let's see a simple example: #include <iostream> #include <set> using namespace std; int main() { multiset<int> c; c.insert(5); c.insert(2); c.insert(4); c.insert(2); c.insert(0); c.insert(5); multiset<int>::iterator i = c.begin(); while (i != c.end()) cout << *i++ << " "; cout << endl; } Output: 0 2 2 4 5 5 Example 3Let's see a simple example to iterate over the multiset using while loop: #include <iostream> #include <set> #include <string> int main() { using namespace std; multiset<string> mymultiset = { "Nikita","Deep","Priya","Suman","Aman","Nikita" }; cout<<"Elements of mymultiset are: "<<endl; multiset<string>::const_iterator it; // declare an iterator it = mymultiset.begin(); // assign it to the start of the multiset while (it != mymultiset.end()) // 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: Elements of mymultiset are: Aman Deep Nikita Nikita Priya Suman In the above example, begin() function is used to return an iterator pointing to the first element in the mymultiset multiset. Example 4Let's see a simple example: #include <set> #include <iostream> int main( ) { using namespace std; multiset <int> s1; multiset <int>::iterator s1_Iter; s1.insert( 1 ); s1.insert( 2 ); s1.insert( 3 ); 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 ); s1_Iter = s1.begin( ); cout << "The first element of s1 is now " << *s1_Iter << endl; } Output: The first element of s1 is 1 The first element of s1 is now 2 In the above example, begin() function is used to return an iterator pointing to the first element in the mymultiset multiset.
Next TopicC++ multiset
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