Difference between revisions of "cpp/string/byte/strcoll"
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===Return value=== | ===Return value=== | ||
| − | Negative value if {{c|lhs}} is ''less than'' (precedes) {{c|rhs}}. | + | * Negative value if {{c|lhs}} is ''less than'' (precedes) {{c|rhs}}. |
| − | + | * {{c|0}} if {{c|lhs}} is ''equal to'' {{c|rhs}}. | |
| − | {{c|0}} if {{c|lhs}} is ''equal to'' {{c|rhs}}. | + | * Positive value if {{c|lhs}} is ''greater than'' (follows) {{c|rhs}}. |
| − | + | ||
| − | Positive value if {{c|lhs}} is ''greater than'' (follows) {{c|rhs}}. | + | |
===Notes=== | ===Notes=== | ||
| Line 28: | Line 26: | ||
#include <cstring> | #include <cstring> | ||
#include <iostream> | #include <iostream> | ||
| − | + | ||
int main() | int main() | ||
{ | { | ||
| − | std::setlocale(LC_COLLATE, "cs_CZ. | + | std::setlocale(LC_COLLATE, "cs_CZ.utf8"); |
| − | + | // Alternatively, ISO-8859-2 (a.k.a. Latin-2) | |
| + | // may also work on some OS: | ||
| + | // std::setlocale(LC_COLLATE, "cs_CZ.iso88592"); | ||
| + | |||
const char* s1 = "hrnec"; | const char* s1 = "hrnec"; | ||
const char* s2 = "chrt"; | const char* s2 = "chrt"; | ||
| − | + | ||
std::cout << "In the Czech locale: "; | std::cout << "In the Czech locale: "; | ||
if (std::strcoll(s1, s2) < 0) | if (std::strcoll(s1, s2) < 0) | ||
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{{dsc end}} | {{dsc end}} | ||
| − | + | {{langlinks|de|es|fr|it|ja|pt|ru|zh}} | |
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Latest revision as of 11:48, 13 October 2023
| Defined in header <cstring>
|
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| int strcoll( const char* lhs, const char* rhs ); |
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Compares two null-terminated byte strings according to the current locale as defined by the LC_COLLATE category.
Contents |
[edit] Parameters
| lhs, rhs | - | pointers to the null-terminated byte strings to compare |
[edit] Return value
- Negative value if lhs is less than (precedes) rhs.
- 0 if lhs is equal to rhs.
- Positive value if lhs is greater than (follows) rhs.
[edit] Notes
Collation order is the dictionary order: the position of the letter in the national alphabet (its equivalence class) has higher priority than its case or variant. Within an equivalence class, lowercase characters collate before their uppercase equivalents and locale-specific order may apply to the characters with diacritics. In some locales, groups of characters compare as single collation units. For example, "ch" in Czech follows "h" and precedes "i", and "dzs" in Hungarian follows "dz" and precedes "g".
[edit] Example
Run this code
#include <clocale> #include <cstring> #include <iostream> int main() { std::setlocale(LC_COLLATE, "cs_CZ.utf8"); // Alternatively, ISO-8859-2 (a.k.a. Latin-2) // may also work on some OS: // std::setlocale(LC_COLLATE, "cs_CZ.iso88592"); const char* s1 = "hrnec"; const char* s2 = "chrt"; std::cout << "In the Czech locale: "; if (std::strcoll(s1, s2) < 0) std::cout << s1 << " before " << s2 << '\n'; else std::cout << s2 << " before " << s1 << '\n'; std::cout << "In lexicographical comparison: "; if (std::strcmp(s1, s2) < 0) std::cout << s1 << " before " << s2 << '\n'; else std::cout << s2 << " before " << s1 << '\n'; }
Output:
In the Czech locale: hrnec before chrt In lexicographical comparison: chrt before hrnec
[edit] See also
| compares two wide strings in accordance to the current locale (function) | |
| [virtual] |
compares two strings using this facet's collation rules (virtual protected member function of std::collate<CharT>)
|
transform a string so that strcmp would produce the same result as strcoll (function) | |
| C documentation for strcoll
| |
