Lambda Expressions

A lambda expression, or lambda, is a convenient way to define an anonymous function object right at the location where it is needed. Lambdas are particularly useful when working with STL algorithms that take a callable entity as an argument, such as `std::sort`, `std::for_each`, or `std::find_if`. The basic syntax of a lambda is `[capture](parameters) -> return_type { body; }`. Let's break this down. The `[]` is the capture clause, which specifies which variables from the surrounding scope the lambda can access. You can capture by value (`[=]`), by reference (`[&]`), or list specific variables (`[var1, &var2]`). The `()` is the parameter list, just like a regular function. The `-> return_type` is optional; if omitted, the compiler will try to deduce the return type from the `return` statements in the body. The `{}` contains the body of the lambda function. For example, to find the first even number in a vector, you could use `std::find_if(vec.begin(), vec.end(), [](int n) { return n % 2 == 0; });`. Here, `[](int n) { return n % 2 == 0; }` is a lambda that takes an integer `n` and returns `true` if it's even. Lambdas make the code more concise and readable because the logic is defined right where it's used, avoiding the need to define a separate named function or a functor class for a simple, one-off operation.