Sorting Strings with Collation Keys

SourcePro : Internationalization Module User’s Guide : Collation : Using Collation Keys : Sorting Strings with Collation Keys

A common use of collation keys is in sorting a set of strings, where string comparisons are made repeatedly, as demonstrated in the code below:

RWUConversionContext context("UTF-8"); //1

RWUString array[] = { //2

"United States",

"Netherlands",

"United Kingdom",

"Germany",

"France",

"Italy",

"Japan",

"Australia",

};

RWUCollator collator; //3

RWTValSortedVector<RWUCollationKey, //4

std::less<RWUCollationKey> > vector;

int i;

for (i = 0; array[i].isNull() == false; ++i) {

vector.insert(collator.getCollationKey(array[i])); //5

}

for (i = 0; i < vector.entries(); ++i) { //6

std::cout << " " << vector[i].getString() << std::endl;

}

//1 Indicates that source and target strings are encoded as UTF-8.

//2 Creates an array of country names.

//3 Creates a collator based on the default locale.

//4 Creates an empty vector. An RWTValSortedVector<T> automatically keeps its contents in sorted order.

//5 Populates the vector with RWUCollationKey objects. Note that the vector uses RWUCollationKey::operator<() and operator==() for sorting.

//6 Prints the sorted vector. Obtains each RWUString object from the stored RWUCollationKey object using getString(), implicitly converts it to UTF-8, and prints the UTF-8.