table of contents
std::vector::front(3) | C++ Standard Libary | std::vector::front(3) |
NAME¶
std::vector::front - std::vector::front
Synopsis¶
reference front(); (until C++20)
constexpr reference front(); (since C++20)
const_reference front() const; (until C++20)
constexpr const_reference front() const; (since C++20)
Returns a reference to the first element in the container.
Calling front on an empty container is undefined.
Parameters¶
(none)
Return value¶
reference to the first element
Complexity¶
Constant
Notes¶
For a container c, the expression c.front() is equivalent to *c.begin().
Example¶
The following code uses front to display the first element of a std::vector<char>:
// Run this code
#include <vector>
#include <iostream>
int main()
{
std::vector<char> letters {'o', 'm', 'g', 'w', 't', 'f'};
if (!letters.empty()) {
std::cout << "The first character is '" <<
letters.front() << "'.\n";
}
}
Output:¶
The first character is 'o'.
See also¶
back access the last element
(public member function)
2022.07.31 | http://cppreference.com |