C++ How to Program, 10/e

... characters are input (e.g., when you attempt to read a number and the user enters a string). In this case, the function returns 0 (false). When such an error occurs on input, the characters are not lost. Usually, recovering from such input errors is possible.

Member Function bad

Line 14 uses the bad member function to determine whether a stream operation failed. The function checks the value of the stream’s badbit data member, which is set to true for a stream when an error occurs that results in the loss of data—such as reading from a file when the disk on which the file is stored fails. In this case, the function returns 0 (false). Generally, such serious failures are nonrecoverable.

Member Function good

Line 15 uses the good member function, which ...