C++ How to Program, 10/e

... vector’s first and last elements, respectively. Notice the difference between functions front and begin. Function front returns a reference to the first element in the vector, while function begin returns a random-access iterator pointing to the first element in the vector. Also notice the difference between functions back and end. Function back returns a reference to the vector’s last element, whereas function end returns a random access iterator pointing to the location after the last element.

Common Programming Error 15.2

The results of front and back are undefined when called on an empty vector.

Accessing vector Elements

Lines 23–24 illustrate ...