std::basic_string<CharT,Traits,Allocator>::resize
< cpp | string | basic string
void resize( size_type count ); |
(1) | |
void resize( size_type count, CharT ch ); |
(2) | |
Resizes the string to contain count
characters.
If the current size is less than count
, additional characters are appended.
If the current size is greater than count
, the string is reduced to its first count
elements.
The first version initializes new characters to CharT(), the second version initializes new characters to ch
.
Parameters
count | - | new size of the string |
ch | - | character to initialize the new characters with |
Return value
(none)
Exceptions
std::length_error if count > max_size().
Any exceptions thrown by corresponding Allocator
.
If an exception is thrown for any reason, this function has no effect (strong exception guarantee). (since C++11)
Example
Run this code
#include <iostream> #include <stdexcept> int main() { std::cout << "Basic functionality:\n"; const unsigned desired_length(8); std::string long_string( "Where is the end?" ); std::string short_string( "Ha" ); // Shorten std::cout << "Before: \"" << long_string << "\"\n"; long_string.resize( desired_length ); std::cout << "After: \"" << long_string << "\"\n"; // Lengthen std::cout << "Before: \"" << short_string << "\"\n"; short_string.resize( desired_length, 'a' ); std::cout << "After: \"" << short_string << "\"\n"; std::cout << "\nErrors:\n"; { std::string s; try { // size is OK, no length_error // (may throw bad_alloc) s.resize(s.max_size() - 1, 'x'); } catch (const std::bad_alloc&) { std::cout << "1. bad alloc\n"; } try { // size is OK, no length_error // (may throw bad_alloc) s.resize(s.max_size(), 'x'); } catch (const std::bad_alloc& exc) { std::cout << "2. bad alloc\n"; } try { // size is BAD, throw length_error s.resize(s.max_size() + 1, 'x'); } catch (const std::length_error&) { std::cout << "3. length error\n"; } } }
Possible output:
Basic functionality: Before: "Where is the end?" After: "Where is" Before: "Ha" After: "Haaaaaaa" Errors: 1. bad alloc 2. bad alloc 3. length error
Complexity
Linear in the size of the string.
See also
returns the number of characters (public member function) |