Cpp Standard Library 简明教程

C++ Library - <ios>

Introduction

C 标准库提供了一套广泛的输入/输出功能，我们将在随后的章节中看到。本章将讨论 C 语言编程所需的非常基础且最常用的 I/O 操作。

The C standard libraries provide an extensive set of input/output capabilities which we will see in subsequent chapters. This chapter will discuss very basic and most common I/O operations required for C programming.

IOStream 类层次结构的输入输出基本类和类型，如下所示：

Input-Output base classes and types for the IOStream hierarchy of classes as shown below −

Types

Class templates

Sr.No.

Member types

Definition

1

basic_ios

Base class for streams (type-dependent components

2

fpos

Stream position class template

Classes

Sr.No.

Member types

Definition

1

ios

Base class for streams (type-dependent components)

2

ios_base

Base class for streams

3

wios

Base class for wide character streams

Other types

Sr.No.

Member types

Definition

1

io_errc

Input/output error conditions

2

streamoff

Stream offset type

3

streampos

Stream position type

4

streamsize

Stream size type

5

wstreampos

Wide stream position type

Format flag manipulators (functions)

独立的标志（开关开启）−

Independent flags (switch on) −

Sr.No.

Member types

Definition

1

boolalpha

Alphanumerical bool values

2

showbase

Show numerical base prefixes

3

showpoint

Show decimal point

4

showpos

Show positive signs

5

skipws

Skip whitespaces

6

unitbuf

Flush buffer after insertions

7

uppercase

Generate upper-case letters

独立的标志（开关关闭）−

Independent flags (switch off) −

Sr.No.

Member types

Definition

1

noboolalpha

No alphanumerical bool values

2

noshowbase

Do not show numerical base prefixes

3

noshowpoint

Do not show decimal point

4

noshowpos

Do not show positive signs

5

noskipws

Do not skip whitespaces

6

nounitbuf

Do not force flushes after insertions

7

nouppercase

Do not generate upper case letters

数字基础格式标志（“basefield” 标志） −

Numerical base format flags ("basefield" flags) −

Sr.No.

Member types

Definition

1

dec

Use decimal base

2

hex

Use hexadecimal base

3

oct

Use octal base

浮点格式标志（“floatfield” 标志） −

Floating-point format flags ("floatfield" flags) −

Sr.No.

Member types

Definition

1

fixed

Use fixed floating-point notation

2

scientific

Use scientific floating-point notation

调整格式标志（“adjustfield” 标志） −

Adustment format flags ("adjustfield" flags) −

Sr.No.

Member types

Definition

1

internal

Adjust field by inserting characters at an internal position

2

left

Adjust output to the left

3

right

Adjust output to the right