C++ <list> front function
frontis used in list toGet the first elementof the function.
frontIt is a member function of the container class, used to return the first element of the linked list.
The time complexity is O(1).
Word Definitions： frontIt means "front", i.e., get the first element.
Basic syntax and parameters
Syntax format
reference front(); const_reference front() const;
Function description
- Return Value: Returns a reference to the first element.
- Note: The linked list cannot be empty.
Example
Example 1: Get the first element
Example
#include <iostream>
#include <list>
int main() {
std::list<int> numbers = {10, 20, 30, 40, 50};
std::cout << First element: << numbers.front() << std::endl;
// modify the first element
numbers.front() = 100;
std::cout << Modified first element: << numbers.front() << std::endl;
return 0;
}
#include <list>
int main() {
std::list<int> numbers = {10, 20, 30, 40, 50};
std::cout << First element: << numbers.front() << std::endl;
// modify the first element
numbers.front() = 100;
std::cout << Modified first element: << numbers.front() << std::endl;
return 0;
}
Expected output:
第一个元素: 10 修改后第一个元素: 100
other extensions