What functions does the ICollection interface implement in standard libraries?

The ICollection interface in C# defines the basic methods and properties for working with collections. Key functions include:

• Getting the number of elements via the Count property.
• Adding and removing elements (depending on the implementation).
• Checking for the presence of an element via the Contains method.
• Copying elements to an array using CopyTo.
• Supporting iteration over elements via IEnumerable.

Example usage:

ICollection<string> collection = new List<string>();
collection.Add("apple");
int count = collection.Count; // 1
bool hasApple = collection.Contains("apple");