C++ Primer Plus

Using Unadorned cin for Input

If a program is going to use a loop to read text input from the keyboard, it has to have some way of knowing when to stop. How can it know when to stop? One way is to choose some special character, sometimes called a sentinel character, to act as a stop sign. For example, Listing 5.16 stops reading input when the program encounters a # character. The program counts the number of characters it reads and then echoes them. That is, it redisplays the characters that have been read. (Pressing a keyboard key doesn’t automatically place a character onscreen; programs have to do that drudge work by echoing the input character. Typically, the operating system handles that task. In this case, both the operating system and ...