wstring (3C++std) - Tru64 UNIX
Standard C++ LibraryCopyright 1996, Rogue Wave Software, Inc.
NAME
basic_string,string - A templated class for handling sequences of
character-like entities. string and wstring are specialized versions of
basic_string for chars and wchar_ts, respectively.
This page describes the ANSI basic_string class. If you would like
information on the pre-ANSI string class, use the command:
man 3C++ String or man String.3C++
typedef basic_string <char> string;
typedef basic_string <wchar_t> wstring;
SYNOPSIS
#include <string>
template <class charT,
class traits = char_traits<charT>,
class Allocator = allocator<charT> >
class basic_string;
DESCRIPTION
basic_string<charT, traits, Allocator> is a homogeneous collection of
character-like entities. It provides general string functionality such as
compare, append, assign, insert, remove, and replace , along with various
searches. basic_string also functions as an STL sequence container,
providing random access iterators. This allows some of the generic
algorithms to apply to strings.
Any underlying character-like type may be used as long as an appropriate
string_char_traits class is provided or the default traits class is
applicable.
INTERFACE
template <class charT,
class traits = char_traits<charT>,
class Allocator = allocator<charT> >
class basic_string {
public:
// Types
typedef traits traits_type;
typedef typename traits::char_type value_type;
typedef Allocator allocator_type;
typename size_type;
typename difference_type;
typename reference;
typename const_reference;
typename pointer;
typename const_pointer;
typename iterator;
typename const_iterator;
typename const_reverse_iterator;
typename reverse_iterator;
static const size_type npos = -1;
// Constructors/Destructors
explicit basic_string(const Allocator& = Allocator());
basic_string (const basic_string<charT, traits, Allocator>&);
basic_string(const basic_string&, size_type, size_type = npos);
basic_string(const charT*, size_type,
const Allocator& = Allocator());
basic_string(const charT*, Allocator& = Allocator());
basic_string(size_type, charT,
const Allocator& = Allocator());
template <class InputIterator>
basic_string(InputIterator, InputIterator,
const Allocator& = Allocator());
~basic_string();
// Assignment operators
basic_string& operator=(const basic_string&);
basic_string& operator=(const charT*);
basic_string& operator=(charT);
// Iterators
iterator begin();
const_iterator begin() const;
iterator end();
const_iterator end() const;
reverse_iterator rbegin();
const_reverse_iterator rbegin() const;
reverse_iterator rend();
const_reverse_iterator rend() const;
// Capacity
size_type size() const;
size_type length() const;
size_type max_size() const;
void resize(size_type, charT);
void resize(size_type);
size_type capacity() const;
void reserve(size_type);
bool empty() const;
// Element access
const_reference operator[](size_type) const;
reference operator[](size_type);
const_reference at(size_type) const;
reference at(size_type);
// Modifiers
basic_string& operator+=(const basic_string&);
basic_string& operator+=(const charT*);
basic_string& operator+=(charT);
basic_string& append(const basic_string&);
basic_string& append(const basic_string&,
size_type, size_type);
basic_string& append(const charT*, size_type);
basic_string& append(const charT*);
basic_string& append(size_type, charT);
template<class InputIterator>
basic_string& append(InputIterator, InputIterator);
basic_string& assign(const basic_string&);
basic_string& assign(const basic_string&,
size_type, size_type);
basic_string& assign(const charT*, size_type);
basic_string& assign(const charT*);
basic_string& assign(size_type, charT);
template<class InputIterator>
basic_string& assign(InputIterator, InputIterator);
basic_string& insert(size_type, const basic_string&);
basic_string& insert(size_type, const basic_string&,
size_type, size_type);
basic_string& insert(size_type, const charT*, size_type);
basic_string& insert(size_type, const charT*);
basic_string& insert(size_type, size_type, charT);
iterator insert(iterator, charT = charT());
void insert(iterator, size_type, charT);
template<class InputIterator>
void insert(iterator, InputIterator,
InputIterator);
basic_string& erase(size_type = 0, size_type= npos);
iterator erase(iterator);
iterator erase(iterator, iterator);
basic_string& replace(size_type, size_type,
const basic_string&);
basic_string& replace(size_type, size_type,
const basic_string&,
size_type, size_type);
basic_string& replace(size_type, size_type,
const charT*, size_type);
basic_string& replace(size_type, size_type,
const charT*);
basic_string& replace(size_type, size_type,
size_type, charT);
basic_string& replace(iterator, iterator,
const basic_string&);
basic_string& replace(iterator, iterator,
const charT*, size_type);
basic_string& replace(iterator, iterator,
const charT*);
basic_string& replace(iterator, iterator,
size_type, charT);
template<class InputIterator>
basic_string& replace(iterator, iterator,
InputIterator, InputIterator);
size_type copy(charT*, size_type, size_type = 0);
void swap(basic_string<charT, traits, Allocator>&);
// String operations
const charT* c_str() const;
const charT* data() const;
const allocator_type& get_allocator() const;
size_type find(const basic_string&,
size_type = 0) const;
size_type find(const charT*,
size_type, size_type) const;
size_type find(const charT*, size_type = 0) const;
size_type find(charT, size_type = 0) const;
size_type rfind(const basic_string&,
size_type = npos) const;
size_type rfind(const charT*,
size_type, size_type) const;
size_type rfind(const charT*,
size_type = npos) const;
size_type rfind(charT, size_type = npos) const;
size_type find_first_of(const basic_string&,
size_type = 0) const;
size_type find_first_of(const charT*,
size_type, size_type) const;
size_type find_first_of(const charT*,
size_type = 0) const;
size_type find_first_of(charT, size_type = 0) const;
size_type find_last_of(const basic_string&,
size_type = npos) const;
size_type find_last_of(const charT*,
size_type, size_type) const;
size_type find_last_of(const charT*, size_type = npos) const;
size_type find_last_of(charT, size_type = npos) const;
size_type find_first_not_of(const basic_string&,
size_type = 0) const;
size_type find_first_not_of(const charT*,
size_type, size_type) const;
size_type find_first_not_of(const charT*, size_type = 0) const;
size_type find_first_not_of(charT, size_type = 0) const;
size_type find_last_not_of(const basic_string&,
size_type = npos) const;
size_type find_last_not_of(const charT*,
size_type, size_type) const;
size_type find_last_not_of(const charT*,
size_type = npos) const;
size_type find_last_not_of(charT, size_type = npos) const;
basic_string substr(size_type = 0, size_type = npos) const;
int compare(const basic_string&) const;
int compare(size_type, size_type, const basic_string&) const;
int compare(size_type, size_type, const basic_string&,
size_type, size_type) const;
int compare(size_type, size_type, charT*) const;
int compare(charT*) const;
int compare(size_type, size_type, const charT*, size_type) const;
};
// Non-member Operators
template <class charT, class traits, class Allocator>
basic_string operator+ (const basic_string&,
const basic_string&);
template <class charT, class traits, class Allocator>
basic_string operator+ (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
basic_string operator+ (charT, const basic_string&);
template <class charT, class traits, class Allocator>
basic_string operator+ (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
basic_string operator+ (const basic_string&, charT);
template <class charT, class traits, class Allocator>
bool operator== (const basic_string&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator== (const charT*, const basic_string&);
template <class charT, class traits , class Allocator>
bool operator== (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
bool operator< (const basic_string&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator< (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator< (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
bool operator!= (const basic_string&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator!= (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator!= (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
bool operator> (const basic_&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator> (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator> (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
bool operator<= (const basic_string&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator<= (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator<= (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
bool operator>= (const basic_string&, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator>= (const charT*, const basic_string&);
template <class charT, class traits, class Allocator>
bool operator>= (const basic_string&, const charT*);
template <class charT, class traits, class Allocator>
void swap(basic_string<charT,traits,Allocator>& a,
basic_string<charT,traits,Allocator>& b);
template<class charT, class traits, class Allocator>
istream& operator>> (istream&, basic_string&);
template <class charT, class traits, class Allocator>
ostream& operator<< (ostream&, const basic_string&);
template <class Stream, class charT,
class traits, class Allocator>
Stream& getline (Stream&, basic_string&, charT);
CONSTRUCTORS AND DESTRUCTORS
In all cases, the Allocator parameter will be used for storage management.
explicit
basic_string (const Allocator& a = Allocator());
The default constructor. Creates a basic_string with the following
effects:
data() a non-null pointer that is copyable and can have 0 added to it
size() 0
capacity() an unspecified value
basic_string (const basic_string<T, traits, Allocator>& str);
Copy constructor. Creates a string that is a copy of str.
basic_string (const basic_string &str, size_type pos,
size_type n= npos);
Creates a string if pos<=size() and determines length rlen
of initial string value as the smaller of n and str.size()
- pos. This has the following effects:
data() points at the first element of an allocated copy
of rlen elements of the string controlled by str
beginning at position pos
size() rlen
capacity() a value at least as large as size()
get_allocator() str.get_allocator()
An out_of_range exception will be thrown if pos>str.size().
basic_string (const charT* s, size_type n,
const Allocator& a = Allocator());
Creates a string that contains the first n characters of s.
s must not be a NULL pointer. The effects of this
constructor are:
data() points at the first element of an allocated copy
of the array whose first element is pointed at by
s
size() n
capacity() a value at least as large as size()
An out_of_range exception will be thrown if n == npos.
basic_string (const charT * s,
const Allocator& a = Allocator());
Constructs a string containing all characters in s up to,
but not including, a traits::eos() character. s must not be
a null pointer. The effects of this constructor are:
data() points at the first element of an allocated copy
of the array whose first element is pointed at by
s
size() traits::length(s)
capacity() a value at least as large as size()
basic_string (size_type n, charT c,
const Allocator& a = Allocator());
Constructs a string containing n repetitions of c. A
length_error exception is thrown if n == npos. The effects
of this constructor are:
data() points at the first element of an allocated array
of n elements, each storing the initial value c
size() n
capacity() a value at least as large as size()
template <class InputIterator>
basic_string (InputIterator first, InputIterator last,
const Allocator& a = Allocator());
Creates a basic_string of length last - first, filled with
all values obtained by dereferencing the InputIterators on
the range [first, last). The effects of this constructor
are:
data() points at the first element of an allocated copy
of the elements in the range [first,last)
size() distance between first and last
capacity() a value at least as large as size()
~basic_string ();
Releases any allocated memory for this basic_string.
OPERATORS
basic_string&
operator= (const basic_string& str);
Assignment operator. Sets the contents of this string to be the same as
str. The effects of operator= are:
data() points at the first element of an allocated copy of the array
whose first element is pointed at by str.size()
size() str.size()
capacity() a value at least as large as size()
basic_string&
operator= (const charT * s);
Assignment operator. Sets the contents of this string to be the same as
s up to, but not including, the traits::eos() character.
basic_string&
operator= (charT c);
Assignment operator. Sets the contents of this string to be equal to the
single charT c.
const_reference
operator[] (size_type pos) const;
reference
operator[] (size_type pos);
If pos < size(), returns the element at position pos in this string.
If pos == size(), the const version returns traits::eos(), the behavior
of the non-const version is undefined. The reference returned by either
version is invalidated by any call to c_str(), data(), or any non-const
member function for the object.
basic_string&
operator+= (const basic_string& s);
basic_string&
operator+= (const charT* s);
basic_string&
operator+= (charT c);
Concatenates a string onto the current contents of this string. The
second member operator uses traits::length() to determine the number of
elements from s to add. The third member operator adds the single
character c. All return a reference to this string after completion.
ITERATORS
iterator begin ();
const_iterator begin () const;
Return an iterator initialized to the first element of the string.
iterator end ();
const_iterator end () const;
Return an iterator initialized to the position after the last element of
the string.
reverse_iterator rbegin ();
const_reverse_iterator rbegin () const;
Returns an iterator equivalent to reverse_iterator(end()).
reverse_iterator rend ();
const_reverse_iterator rend () const;
Returns an iterator equivalent to reverse_iterator(begin()).
ALLOCATOR
const allocator_type get_allocator () const;
Returns a copy of the allocator used by self for storage management.
MEMBER FUNCTIONS
basic_string&
append (const basic_string& s, size_type pos, size_type npos);
basic_string&
append (const basic_string& s);
basic_string&
append (const charT* s, size_type n);
basic_string&
append (const charT* s);
basic_string&
append (size_type n, charT c );
template<class InputIterator>
basic_string&
append (InputIterator first, InputIterator last);
Append another string to the end of this string. The first two
functions append the lesser of n and s.size() - pos characters of s,
beginning at position pos to this string. The second member will throw
an out_of_range exception if pos > str.size(). The third member appends
n characters of the array pointed to by s. The fourth variation appends
elements from the array pointed to by s up to, but not including, a
traits::eos() character. The fifth variation appends n repetitions of
c. The final append function appends the elements specified in the
range [first, last).
All functions will throw a length_error exception if the resulting
length will exceed max_size(). All return a reference to this string
after completion.
basic_string&
assign (const basic_string& s);
basic_string&
assign (const basic_string& s,
size_type pos, size_type n);
basic_string&
assign (const charT* s, size_type n);
basic_string&
assign (const charT* s);
basic_string&
assign (size_type n, charT c );
template<class InputIterator>
basic_string&
assign (InputIterator first, InputIterator last);
Replace the value of this string with the value of another.
All versions of the function assign values to this string. The first
two variations assign the lesser of n and s.size() - pos characters of
s, beginning at position pos. The second variation throws an
out_of_range exception if pos > str.size(). The third version of the
function assigns n characters of the array pointed to by s. The fourth
version assigns elements from the array pointed to by s up to, but not
including, a traits::eos() character. The fifth assigns one or n
repetitions of c. The last variation assigns the members specified by
the range [first, last).
All functions will throw a length_error exception if the resulting
length will exceed max_size(). All return a reference to this string
after completion.
const_reference
at (size_type pos) const;
reference
at (size_type pos);
If pos < size(), returns the element at position pos in this string.
Otherwise, an out_of_range exception is thrown.
size_type
capacity () const;
Returns the current storage capacity of the string. This is guaranteed
to be at least as large as size().
int
compare (const basic_string& str);
Returns the result of a lexicographical comparison between elements of
this string and elements of str. The return value is:
<0 if size() < str.size()
0 if size() == str.size()
>0 if size() > str.size()
int
compare (size_type pos1, size_type n1,
const basic_string& str) const;
int
compare (size_type pos1, size_type n1, const basic_string& str,
size_type pos2, size_type n2) const;
int
compare (charT* s) const;
int
compare (size_type pos, size_type n1, charT* s) const;
int
compare (size_type pos, size_type n1, charT* s,
size_type n2) const;
Return the result of a lexicographical comparison between
elements of this string and a given comparison string. The
members return, respectively:
compare (str)
compare (basic_string (str, pos2, n2))
compare (basic_string(s))
compare (basic_string(s, npos))
compare (basic_string (s,n2))
size_type
copy (charT* s, size_type n, size_type pos = 0) const;
Replaces elements in memory with copies of elements from this string.
An out_of_range exception will be thrown if pos > size(). The lesser of
n and size() - pos elements of this string, starting at position pos
are copied into the array pointed to by s. No terminating null is
appended to s.
const charT*
c_str () const;
const charT*
data () const;
Return a pointer to the initial element of an array whose first size()
elements are copies of the elements in this string. A traits::eos()
element is appended to the end. The elements of the array may not be
altered, and the returned pointer is only valid until a non-const member
function of this string is called. If size() is zero, the data()
function returns a NULL pointer.
bool empty () const;
Returns size() == 0.
basic_string&
erase (size_type pos = 0, size_type n = npos);
iterator
erase (iterator p);
iterator
erase (iterator first, iterator last);
This function removes elements from the string, collapsing the remaining
elements, as necessary, to remove any space left empty. The first
version of the function removes the smaller of n and size() - pos
starting at position pos. An out_of_range exception will be thrown if
pos > size(). The second version requires that p is a valid iterator
on this string, and removes the character referred to by p. The last
version of erase requires that both first and last are valid iterators
on this string, and removes the characters defined by the range [first,
last). The destructors for all removed characters are called. All
versions of erase return a reference to this string after completion.
size_type
find (const basic_string& str, size_type pos = 0) const;
Searches for the first occurrence of the substring specified by str in
this string, starting at position pos. If found, it returns the index
of the first character of the matching substring. If not found, returns
npos. Equality is defined by traits::eq().
size_type
find (const charT* s, size_type pos, size_type n) const;
size_type
find (const charT* s, size_type pos = 0) const;
size_type
find (charT c, size_type pos = 0) const;
Search for the first sequence of characters in this string that match a
specified string. The variations of this function return, respectively:
find(basic_string(s,n), pos)
find(basic_string(s), pos)
find(basic_string(1, c), pos)
size_type
find_first_not_of (const basic_string& str,
size_type pos = 0) const;
Searches for the first element of this string at or
after position pos that is not equal to any element of
str. If found, find_first_not_of returns the index of
the non-matching character. If all of the characters
match, the function returns npos. Equality is defined
by traits::eq().
size_type
find_first_not_of (const charT* s,
size_type pos, size_type n) const;
size_type
find_first_not_of (const charT* s,
size_type pos = 0) const;
size_type
find_first_not_of (charT c, size_type pos = 0) const;
Search for the first element in this string at or after position pos
that is not equal to any element of a given set of characters. The
members return, respectively:
find_first_not_of(basic_string(s,n), pos)
find_first_not_of(basic_string(s), pos)
find_first_not_of(basic_string(1, c), pos)
size_type
find_first_of(const basic_string& str,
size_type pos = 0) const;
Searches for the first occurrence at or after position pos
of any element of str in this string. If found, the index
of this matching character is returned. If not found,
npos is returned. Equality is defined by traits::eq().
size_type
find_first_of(const charT* s, size_type pos,
size_type n) const;
size_type
find_first_of(const charT* s, size_type pos = 0) const;
size_type
find_first_of (charT c, size_type pos = 0) const;
Search for the first occurrence in this string of any element in a
specified string. The find_first_of variations return, respectively:
find_first_of(basic_string(s,n), pos)
find_first_of(basic_string(s), pos)
find_first_of(basic_string(1, c), pos)
size_type
find_last_not_of(const basic_string& str,
size_type pos = npos) const;
Searches for the last element of this string at or
before position pos that is not equal to any element of
str. If find_last_not_of finds a non-matching element,
it returns the index of the character. If all the
elements match, the function returns npos. Equality is
defined by traits::eq().
size_type
find_last_not_of(const charT* s,
size_type pos, size_type n) const;
size_type
find_last_not_of(const charT* s, size_type pos = npos) const;
size_type
find_last_not_of(charT c, size_type pos = npos) const;
Search for the last element in this string at or before position pos
that is not equal to any element of a given set of characters. The
members return, respectively:
find_last_not_of(basic_string(s,n), pos)
find_last_not_of(basic_string(s), pos)
find_last_not_of(basic_string(1, c), pos)
size_type
find_last_of(const basic_string& str,
size_type pos = npos) const;
Searches for the last occurrence of any element of str at or
before position pos in this string. If found, find_last_of
returns the index of the matching character. If not found
find_last_of returns npos. Equality is defined by
traits::eq().
size_type
find_last_of(const charT* s, size_type pos,
size_type n) const;
size_type
find_last_of(const charT* s, size_type pos = npos) const;
size_type
find_last_of(charT c, size_type pos = npos) const;
Search for the last occurrence in this string of any element in a
specified string. The members return, respectively:
find_last_of(basic_string(s,n), pos)
find_last_of(basic_string(s), pos)
find_last_of(basic_string(1, c), pos)
basic_string&
insert(size_type pos1, const basic_string& s);
basic_string&
insert(size_type pos, const basic_string& s,
size_type pos2 = 0, size_type n = npos);
basic_string&
insert(size_type pos, const charT* s, size_type n);
basic_string&
insert(size_type pos, const charT* s);
basic_string&
insert(size_type pos, size_type n, charT c);
Insert additional elements at position pos in this string. All of the
variants of this function will throw an out_of_range exception if pos >
size(). All variants will also throw a length_error if the resulting
string will exceed max_size(). Elements of this string will be moved
apart as necessary to accommodate the inserted elements. All return a
reference to this string after completion.
The second variation of this function inserts the lesser of n and
s.size() - pos2 characters of s, beginning at position pos2 in this
string. This version will throw an out_of_range exception if pos2 >
s.size(). The third version inserts n characters of the array pointed
to by s. The fourth inserts elements from the array pointed to by s up
to, but not including, a traits::eos() character. Finally, the fifth
variation inserts n repetitions of c.
iterator
insert(iterator p, charT c = charT());
void
insert(iterator p, size_type n, charT c);
template<class InputIterator>
void
insert(iterator p, InputIterator first, InputIterator last);
Insert additional elements in this string immediately before the
character referred to by p. All of these versions of insert require
that p is a valid iterator on this string. The first version inserts a
copy of c. The second version inserts n repetitions of c. The third
version inserts characters in the range [first, last). The first
version returns p.
size_type
length() const;
Return the number of elements contained in this string.
size_type
max_size() const;
Returns the maximum possible size of the string.
size_type
rfind (const basic_string& str, size_type pos = npos) const;
Searches for the last occurrence of the substring specified by str in
this string, starting at position pos. Note that only the first
character of the substring must be <= pos; the remaining characters may
extend beyond pos. If found, the index of the first character of that
matches substring is returned. If not found, npos is returned.
Equality is defined by traits::eq().
size_type
rfind(const charT* s, size_type pos, size_type n) const;
size_type
rfind(const charT* s, size_type pos = npos) const;
size_type
rfind(charT c, size_type pos = npos) const;
Searches for the last sequence of characters in this string matching a
specified string. The rfind variations return, respectively:
rfind(basic_string(s,n), pos)
rfind(basic_string(s), pos)
rfind(basic_string(1, c), pos)
basic_string&
replace(size_type pos, size_type n1, const basic_string& s);
basic_string&
replace(size_type pos1, size_type n1, const basic_string& str,
size_type pos2, size_type n2);
basic_string&
replace(size_type pos, size_type n1, const charT* s,
size_type n2);
basic_string&
replace(size_type pos, size_type n1, const charT* s);
basic_string&
replace(size_type pos, size_type n1, size_type n2, charT c);
The replace function replaces selected elements of this string with an
alternate set of elements. All of these versions insert the new
elements in place of n1 elements in this string, starting at position
pos. They each throw an out_of_range exception if pos1 > size()and a
length_error exception if the resulting string size exceeds max_size().
The second version replaces elements of the original string with n2
characters from string s starting at position pos2. It will throw the
out_of_range exception if pos2 > s.size(). The third variation of the
function replaces elements in the original string with n2 elements from
the array pointed to by s. The fourth version replaces elements in the
string with elements from the array pointed to by s, up to, but not
including, a traits::eos() character. The fifth replaces n elements
with n2 repetitions of character c.
basic_string&
replace(iterator i1, iterator i2,
const basic_string& str);
basic_string&
replace(iterator i1, iterator i2, const charT* s,
size_type n);
basic_string&
replace(iterator i1, iterator i2, const charT* s);
basic_string&
replace(iterator i1, iterator i2, size_type n,
charT c);
template<class InputIterator>
basic_string&
replace(iterator i1, iterator i2,
InputIterator j1, InputIterator j2);
Replace selected elements of this string with an alternative set
of elements. All of these versions of replace require iterators
i1 and i2 to be valid iterators on this string. The elements
specified by the range [i1, i2) are replaced by the new elements.
The first version shown here replaces with all members in str.
The second version starts at position i1, and replaces the next
n characters with n characters of the array pointed to by s. The
third variation replaces string elements with elements from the
array pointed to by s up to, but not including, a traits::eos()
character. The fourth version replaces string elements with n
repetitions of c. The last variation shown here replaces string
elements with the members specified in the range [j1, j2).
void
reserve(size_type res_arg);
Assures that the storage capacity is at least res_arg.
void
resize(size_type n, charT c);
void
resize(size_type n);
Changes the capacity of this string to n. If the new capacity is
smaller than the current size of the string, then it is truncated. If
the capacity is larger, then the string is padded with c characters.
The latter resize member pads the string with default characters
specified by traits::eos().
size type
size() const;
Return the number of elements contained in this string.
basic_string
substr(size_type pos = 0, size_type n = npos) const;
Returns a string composed of copies of the lesser of n and size()
characters in this string starting at index pos. Throws an out_of_range
exception if pos <= size().
void
swap(basic_string& s);
Swaps the contents of this string with the contents of s.
NON-MEMBER OPERATORS
template<class charT, class traits, class Allocator>
basic_string
operator+(const basic_string& lhs, const basic_string& rhs);
Returns a string of length lhs.size() + rhs.size(), where the first
lhs.size() elements are copies of the elements of lhs, and the next
rhs.size() elements are copies of the elements of rhs.
template<class charT, class traits, class Allocator>
basic_string
operator+(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
basic_string
operator+(charT lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
basic_string
operator+(const basic_string& lhs, const charT* rhs);
template<class charT, class traits, class Allocator>
basic_string
operator+(const basic_string& lhs, charT rhs);
Returns a string that represents the concatenation of two string-like
entities. These functions return, respectively:
basic_string(lhs) + rhs
basic_string(1, lhs) + rhs
lhs + basic_string(rhs)
lhs + basic_string(1, rhs)
template<class charT, class traits, class Allocator>
bool
operator==(const basic_string& lhs, const basic_string& rhs);
Returns a boolean value of true if lhs and rhs are equal, and false if
they are not. Equality is defined by the compare() member function.
template<class charT, class traits, class Allocator>
bool
operator==(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator==(const basic_string& lhs, const charT* rhs);
Returns a boolean value indicating whether lhs and rhs are equal.
Equality is defined by the compare() member function. These functions
return, respectively:
basic_string(lhs) == rhs
lhs == basic_string(rhs)
template<class charT, class traits, class Allocator>
bool
operator!=(const basic_string& lhs,
const basic_string& rhs);
Returns a boolean value representing the inequality of lhs and
rhs. Inequality is defined by the compare() member function.
template<class charT, class traits, class Allocator>
bool
operator!=(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator!=(const basic_string& lhs, const charT* rhs);
Returns a boolean value representing the inequality of lhs and rhs.
Inequality is defined by the compare() member function. The functions
return, respectively:
basic_string(lhs) != rhs
lhs != basic_string(rhs)
template<class charT, class traits, class Allocator>
bool
operator<(const basic_string& lhs, const basic_string& rhs);
Returns a boolean value representing the lexicographical less-than
relationship of lhs and rhs. Less-than is defined by the compare()
member.
template<class charT, class traits, class Allocator>
bool
operator<(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator<(const basic_string& lhs, const charT* rhs);
Returns a boolean value representing the lexicographical less-than
relationship of lhs and rhs. Less-than is defined by the compare()
member function. These functions return, respectively:
basic_string(lhs) < rhs
lhs < basic_string(rhs)
template<class charT, class traits, class Allocator>
bool
operator>(const basic_string& lhs, const basic_string& rhs);
Returns a boolean value representing the lexicographical greater-than
relationship of lhs and rhs. Greater-than is defined by the compare()
member function.
template<class charT, class traits, class Allocator>
bool
operator>(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator>(const basic_string& lhs, const charT* rhs);
Returns a boolean value representing the lexicographical greater-than
relationship of lhs and rhs. Greater-than is defined by the compare()
member. The functions return, respectively:
basic_string(lhs) > rhs
lhs > basic_string(rhs)
template<class charT, class traits, class Allocator>
bool
operator<=(const basic_string& lhs,
const basic_string& rhs);
Returns a boolean value representing the lexicographical
less-than-or-equal relationship of lhs and rhs. Less-than-
or-equal is defined by the compare() member function.
template<class charT, class traits, class Allocator>
bool
operator<=(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator<=(const basic_string& lhs, const charT* rhs);
Returns a boolean value representing the lexicographical less-than-or-
equal relationship of lhs and rhs. Less-than-or-equal is defined by the
compare() member function. These functions return, respectively:
basic_string(lhs) <= rhs
lhs <= basic_string(rhs)
template<class charT, class traits, class Allocator>
bool
operator>=(const basic_string& lhs, const basic_string& rhs);
Returns a boolean value representing the lexicographical greater-than-
or-equal relationship of lhs and rhs. Greater-than-or-equal is defined
by the compare() member function.
template<class charT, class traits, class Allocator>
bool
operator>=(const charT* lhs, const basic_string& rhs);
template<class charT, class traits, class Allocator>
bool
operator>=(const basic_string& lhs, const charT* rhs);
Returns a boolean value representing the lexicographical greater-than-
or-equal relationship of lhs and rhs. Greater-than-or-equal is defined
by the compare() member. The functions return, respectively:
basic_string(lhs) >= rhs
lhs >= basic_string(rhs)
template <class charT, class traits, class Allocator>
void swap(basic_string<charT,traits,Allocator>& a,
basic_string<charT,traits,Allocator>& b);
Swaps the contents of a and b by calling a's swap function on
b.
template<class charT, class traits, class Allocator>
istream&
operator>>(istream& is, basic_string& str);
Reads str from is using traits::char_in until a traits::is_del()
element is read. All elements read, except the delimiter, are placed
in str. After the read, the function returns is.
template<class charT, class traits, class Allocator>
ostream&
operator<<(ostream& os, const basic_string& str);
Writes all elements of str to os in order from first to last, using
traits::char_out(). After the write, the function returns os.
NON-MEMBER FUNCTION
template <class Stream, class charT, class traits,
class Allocator>
Stream&
getline(Stream& is, basic_string& str, charT delim);
An unformatted input function that extracts characters from is into str
until npos - 1 characters are read, the end of the input sequence is
reached, or the character read is delim. The characters are read using
traits::char_in().
EXAMPLE
//
// string.cpp
//
#include<string>
#include <iostream.h>
int main()
{
string test;
//Type in a string over five characters long
while(test.empty() || test.size() <= 5)
{
cout << "Type a string between 5 and 100 characters long. "
<< endl;
cin >> test;
}
//Test operator[] access
cout << "Changing the third character from " << test[2] <<
" to * " << endl;
test[2] = '*';
cout << "now its: " << test << endl << endl;
//Try the insertion member function
cout << "Identifying the middle: ";
test.insert(test.size() / 2, "(the middle is here!)");
cout << test << endl << endl;
//Try replacement
cout << "I didn't like the word 'middle',so instead,I'll say:"
<< endl;
test.replace(test.find("middle",0), 6, "center");
cout << test << endl;
return 0;
}
Output :
Type a string between 5 and 100 characters long.
roguewave
Changing the third character from g to *
now its: ro*uewave
Identifying the middle: ro*u(the middle is here!)ewave
I didn't like the word 'middle', so instead, I'll say:
ro*u(the center is here!)ewave
SEE ALSO
Allocators, string, wstring
STANDARDS CONFORMANCE
ANSI X3J16/ISO WG21 Joint C++ Committee
privacy and legal statement
