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Introduction to C++ Lists
What are C++ Lists?
C++ Lists are a part of the Standard Template Library (STL) and are used to store a sequence of elements. They are implemented as doubly linked lists, allowing efficient insertion and deletion of elements.
Creating a List in C++
Basic List Creation
To create a list in C++, include the <list> header and use the std::list class. You can specify the type of elements the list will hold.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList;
return 0;
}
Adding Elements to a List
Using push_back and push_front
Elements can be added to the end of the list using push_back and to the beginning using push_front.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList;
myList.push_back(10);
myList.push_front(20);
return 0;
}
Accessing List Elements
Iterating through a List
Use iterators to access and iterate through list elements. Iterators are similar to pointers and can be used with loops.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList = {10, 20, 30};
for(list<int>::iterator it = myList.begin(); it != myList.end(); ++it) {
cout << *it << " ";
}
return 0;
}
Removing Elements from a List
Using pop_back, pop_front, and erase
Elements can be removed from the end using pop_back, from the start using pop_front, or from a specific position using erase.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList = {10, 20, 30};
myList.pop_back();
myList.pop_front();
myList.erase(myList.begin());
return 0;
}
Sorting a List
Using the sort Function
The sort function sorts the elements of the list in ascending order. It uses the default comparison operator.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList = {30, 10, 20};
myList.sort();
return 0;
}
Merging Lists
Using the merge Function
Two lists can be merged into a single list using the merge function. The lists should be sorted prior to merging.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> list1 = {10, 20, 30};
list<int> list2 = {15, 25};
list1.merge(list2);
return 0;
}
Splicing Lists
Using the splice Function
The splice function transfers elements from one list to another. It can be used to move entire lists or specific elements.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> list1 = {10, 20, 30};
list<int> list2 = {40, 50};
list1.splice(list1.end(), list2);
return 0;
}
Reversing a List
Using the reverse Function
The reverse function reverses the order of elements in the list, allowing for backward traversal.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList = {10, 20, 30};
myList.reverse();
return 0;
}
Unique Elements in a List
Using the unique Function
The unique function removes consecutive duplicate elements in a list, ensuring each element appears only once in sequence.
#include <iostream>
#include <list>
using namespace std;
int main() {
list<int> myList = {10, 10, 20, 30, 30};
myList.unique();
return 0;
}
