How do you ensure the correct use of numerals when implementing localization of applications?

For correct usage of numerals in localization in C#, the PluralizationService class or third-party libraries supporting plural rules for different languages are usually used. In .NET Core and .NET 5+, the Humanizer library can be used, which correctly inflects words and numerals.

Example using Humanizer:

using Humanizer;

int count = 5;
string message = $"You have {count} {"message".ToQuantity(count, ShowQuantityAs.None)}.";
// Will output: You have 5 messages.

For more complex rules, such as in Russian where forms depend on the numeral (1, 2-4, 5+), ICU MessageFormat or specialized libraries that consider these rules can be used.

It is important to store localized strings with placeholders and use the correct forms depending on the number to avoid display errors.