Explain what anonymous functions or lambda expressions are in programming.

Anonymous functions or lambda expressions are functions without names that can be defined directly at the point of use. In C#, they allow writing concise code, especially when working with delegates, events, and LINQ.

A lambda expression is written using the => operator, where the parameters are on the left and the body of the function is on the right.

Example:

Func<int, int, int> sum = (a, b) => a + b;
int result = sum(3, 4); // result = 7

Here, (a, b) => a + b is a lambda expression that takes two parameters and returns their sum.

Anonymous functions are convenient for passing small blocks of code as parameters, for example, for sorting or filtering collections.