C++ <list> empty Function
emptyis used in list forcheck whether the linked list is emptyof the function.
emptyIt is a member function of the container class, returning whether the linked list is empty.
This is the most commonly used function to check the state of a linked list, compared tosize() == 0More efficient.
Word Definitions： emptyIt means "empty", i.e., checks whether the linked list is empty.
Basic syntax and parameters
Syntax format
bool empty() const;
Function description
- Return Value: If the linked list is empty, return
true, otherwise returnfalse。
Example
Example 1: Check whether the linked list is empty
Example
#include <iostream>
#include <list>
void processList(const std::list<int>& lst) {
if(lst.empty()) {
std::cout << The list is empty << std::endl;
} else {
std::cout << The list has << lst.size() << " elements" << std::endl;
}
}
int main() {
std::list<int> emptyList;
processList(emptyList);
std::list<int> numbers = {1, 2, 3};
processList(numbers);
return 0;
}
#include <list>
void processList(const std::list<int>& lst) {
if(lst.empty()) {
std::cout << The list is empty << std::endl;
} else {
std::cout << The list has << lst.size() << " elements" << std::endl;
}
}
int main() {
std::list<int> emptyList;
processList(emptyList);
std::list<int> numbers = {1, 2, 3};
processList(numbers);
return 0;
}
Expected running result:
链表为空 链表有 3 个元素
other extensions