C++11-----Basic2

1. Use a using declaration

. Using namespace Spacename

. Using Namespace::name

2. Standard library type String

Initialization

. string S//default NULL string

. String s (S1)//Copy initialization

. String s = S1//Ibid.

. String S ("XXXX")

. String s = "xxxxx"

. string s (n, ' C ')//s initialized to a string consisting of a continuous n-character C

. String s = {' h ', ' e ', ' l ', ' l ', ' 0 '};

Manipulate

Iterator:

Begin ()

End ()

Capacity:

Size ()

Length ()

Capacity ()

Resize ()

Reserve ()

Clear ()

Empty ()

Access:

[]

at ()

Front ()

Back ()

Modifiers:

operator+=

Append ()

Push_back ()

Insert ()

Erase ()

Swap ()

String Operations:

C_str ()

Data ()

Copy ()

Find ()

SUBSTR ()

Compare ()

Compare:

==

!=

> >=

< <=

Other:

is >> s

OS << S

Getline (is, s)

Note:

• Length () & Size (): Length () for C-style, size () for STL introduction
• [] & at (): [] When the subscript of the access is out of range, the result is undefined; at () The scope is checked, the subscript is exceeded, and the Out_of_range exception is thrown
• C_STR () & Data (): C_str () returns a null-terminated pointer to the content, and data () simply returns a pointer to the content that does not include NULL, providing only valid character data
• String object cannot be truncated by ' + ' and is only meaningful in C-style string.

As below, we have written a teststring.cpp program for testing

Compile run:

#g + +-wall-g-std=c++0x teststring.cpp//default generate executable program a.out

#./a.out

Description

1. Initial s initialized to an empty string with a print length of 0

2.s add content, even if there are null characters, the number is also counted, so size is 9;c style string, always to the end of the, so size is 5

3. When a C-style string is initialized or added to a string object, it is truncated, the content is discarded, and the new string object is no longer truncated when it is initialized or added to a new string object using a string object with a \ n, as shown in S2 printing

Appendix:

　　

Figure 1

Figure 2

Note:

The Push_back () function, the length count plus 1 of s, can always be drawn from the S + = ' + ' character from Figure 1.

It is deduced that when the + = C-style string is appended, only the length of strlen (CStr) is added, and when the + = string object is appended with the length of string.size ()

C_STR () & Data ()

Note:

The string object does not identify the end of the strings with a null character (null, ' \ s ')

3. Range for (range for)//c++11 Add

for (range_declaration:range_expresssion)

Loop_statement;

Range_declaration: A variable declaration, which is an element or reference to a sequence of range_expression, usually using auto to detect its type

Range_expression: An expression or curly brace that can be expressed as a sequence to initialize a list

4.vector

Initialization

Vector<t> V

Vector<t> V1 (v)

Vector<t> V1 = V

Vector<t> v {...} Initialize-list

Vector<t> v = {...}

Vector<t> V (N, Val)

Vector<t> V (N)

Other

V.empty ()

V.size ()

V.push_back ()

V[n]

= = = > >= < <=

5. iterators (iterator)

C++11-----Basic2