What is the usage of lambda expressions in C++?

Lambda expressions in C++ are anonymous functions that can be used in place of regular functions or function objects where they are needed. Their syntax is as follows:

Mapping list -> return type {function body}

The capture list, parameter list, and return type are optional in a lambda expression. The function body is where the specific implementation of the lambda expression is written.

Lambda expressions can be utilized in a variety of scenarios, including but not limited to the following:

1. To use as a function object: you can assign a lambda expression to a function object and then call it like a regular function.
2. Lambda expressions can be used as parameters in functions for defining callback functions or sorting functions, for example.
3. Lambda expressions can be used as parameters for container algorithms to define specific operations or comparison rules.
4. Lambda expressions can be used as tasks in concurrent programming to execute in parallel.

The advantage of lambda expressions lies in their simplicity and flexibility, allowing functions to be defined and used directly where needed without the need for additional function definitions.