std::vector<T,Allocator>:: front

Returns a reference to the first element in the container.

Calling front on an empty container causes undefined behavior.

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

#include <cassert>
#include <vector>
 
int main()
{
    std::vector<char> letters{'a', 'b', 'c', 'd'};
    assert(letters.front() == 'a');
}

See also