函数式编程和命令式编程的区别

函数式编程：顾名思义，函数式编程是一种编程范式，它被明确创建，只是为了支持解决问题的纯函数式方法。这种类型的编程主要用于解决方案在函数上很容易表达并且物理意义很小的情况。它只是帮助我们以更简单的方式有效地解决问题。它还允许将函数视为普通值，因为在函数式编程中，函数可以自由地将函数作为参数操作并返回新函数作为返回值。它是声明式编程的一种形式。它被认为是流行的编程范式之一，可以像数学函数一样进行计算而不改变状态和变异数据。

例如： Python、Clojure、Haskell、Lisp 等。

命令式编程：命令式编程，顾名思义，是一种编程范式，它指定计算机为完成或完成目标而应采取的步骤。在这种情况下，函数在解决问题所需的每个步骤中都被隐式编码。简单来说，它包括计算机执行的命令。程序编写速度更快，应用程序也更容易优化。它允许将函数视为特殊情况构造，因为在命令式编程中，很少允许从方法返回整个方法调用。它是算法编程的一种形式。

例如： Java、Fortran、Pascal、C、C++ 等。

函数式编程和命令式编程之间的表格区别：

Functional Programming	Imperative Programming
It is generally a process of developing software simply by composing pure functions, avoiding or minimizing side effects, shared data, and mutable data.	It is generally a process of describing steps that simply change the state of the computer.
It mainly focuses on what programs should be executed or operate i.e., results.	It mainly focuses on describing how the program executes or operates i.e., process.
It uses functions to perform everything.	It uses statements that change a program’s state.
Its advantages include bugs-free code, increase performance, better encapsulation, increase reusability, increase testability, etc.	Its advantages include easy to learn, easy to read, a conceptual model is easy to learn, etc.
Its characteristics include low importance of the order of execution, stateless programming model, primary manipulations units, primary flow control, etc.	Its characteristics include a sequence of statements, contain state and can change state, might have some side effects, stateful programming model, etc.
These programs are generally structured as successive nested functional calls.	These programs are structured as successive assignments of values to variable names.
In this, the command execution order is not fixed.	In this, the command execution order is fixed.
It involves writing programs in terms of functions and mathematical structures.	It involves writing programs as series of instructions or statements that can actively modify memory.
It is more expressive and safer as compared to imperative programming.	It is less expressive and safer than compared functional programming.
It requires the explicit representation of data structures that are used.	It requires data structure to be represented as changes to state.
In this, new values are usually associated with the same name through command repetition.	In this, new values are usually associated with different names through recursive function call nesting.