The________ function is useful in formatting various types of printed output.
Solution: FORMAT is used to produce formatted output. formatoutputs the characters of control-string, except that a tilde (~) introduces a directive. The character after the tilde, possibly preceded by prefix parameters and modifiers, specifies what kind of formatting is desired. Most directives use one or more elements of arguments to create their output; the typical directive puts the next element of arguments into the output, formatted in some special way. It is an error if no argument remains for a directive requiring an argument, but it is not an error if one or more arguments remain unprocessed by a directive.