15. Stream Input/Output

Objectives

In this chapter you'll learn:

  • To use C++ object-oriented stream input/output.

  • To format input and output.

  • The stream-I/O class hierarchy.

  • To use stream manipulators.

  • To control justification and padding.

  • To determine the success or failure of input/output operations.

  • To tie output streams to input streams.

Consciousness ... does not appear to itself chopped up in bits ... A "river" or a "stream" are the metaphors by which it is most naturally described.

—William James

All the news that's fit to print.

—Adolph S. Ochs

Remove not the landmark on the boundary of the fields.

—Amenehope

Outline

15.1 Introduction
15.2 Streams
  15.2.1 Classic Streams vs. Standard Streams
  15.2.2 iostream Library Header Files
  15.2.3 Stream Input/Output Classes and Objects
15.3 Stream Output
  15.3.1 Output of char * Variables
  15.3.2 Character Output Using Member Function put
15.4 Stream Input
  15.4.1 get and getline Member Functions
  15.4.2 istream Member Functions peek, putback and ignore
  15.4.3 Type-Safe I/O
15.5 Unformatted I/O Using read, write and gcount
15.6 Introduction to Stream Manipulators
  15.6.1 Integral Stream Base: dec, oct, hex and setbase
  15.6.2 Floating-Point Precision (precision, setprecision)
  15.6.3 Field Width (width, setw)
  15.6.4 User-Defined Output Stream Manipulators
15.7 Stream Format States and Stream Manipulators
  15.7.1 Trailing Zeros and Decimal Points (showpoint)
  15.7.2 Justification (left, right and internal)
  15.7.3 Padding (fill, setfill)
  15.7.4 Integral Stream Base (dec, oct, hex, showbase)
  15.7.5 Floating-Point Numbers; Scientific and Fixed Notation (scientific, fixed)
  15.7.6 Uppercase/Lowercase Control (uppercase)
  15.7.7 Specifying Boolean Format (boolalpha)
  15.7.8 Setting and Resetting the Format State via Member-Function flags
15.8 Stream Error States
15.9 Tying an Output Stream to an Input Stream
15.10 Wrap-Up