ANSWER

Functional programming is a way of writing computer programs that focuses on using functions to do everything. To explain it in simple terms, think of it like creating a series of clear, step-by-step instructions (like a recipe) where each step (or function) does one thing and does it well, without changing anything else in the process.

Another way is to view the functional programming approach as similar to how a factory works. Each machine (function) in the factory has a specific job. It takes raw materials (inputs), processes them in a specific way, and produces a finished product (output) without affecting other machines. If you need to create a new product, you can combine these machines in different ways without changing how each machine works. This makes the factory efficient, predictable, and easy to manage.

Here are the main ideas of functional programming:

• Functions as Building Blocks
  • Simple Steps - Imagine you have a recipe, and each step in the recipe is a function. Each function takes some ingredients (inputs), does something with them, and produces a result (output). For example, mixing flour and water to make dough is one function.
  • No Side Effects - When you perform a step, it doesn't affect anything outside that step. For example, mixing the dough doesn't suddenly change the oven temperature. Each function is self-contained.

• Immutability of Functions
  • No Changing Ingredients - Once you create something, you don’t change it. If you need a different result, you create something new instead of altering the original. For instance, if you have a bowl of dough and you want to add sugar, you make a new bowl with dough and sugar instead of just adding sugar to the existing dough.
  • Consistency - This makes it easier to follow the recipe and understand what’s happening because the ingredients remain consistent throughout the process.

• Reusing Functions
  • Building Blocks - Just like in cooking, where you might use the same step (like mixing) in multiple recipes, in functional programming, you can reuse functions in different parts of your program. This saves time and effort because you don't have to write the same instructions over and over again.

• Combining Functions
  • Mix and Match - You can combine simple functions to make more complex ones. It’s like combining basic cooking techniques (chopping, mixing, baking) to make a full meal. By putting small functions together, you can build more complex operations.

• Predictable and Easy to Test Functions
  • Consistency - Since functions don’t change anything outside themselves and always produce the same output for the same input, they are predictable. This is like knowing that every time you mix flour and water, you will always get dough.
  • Easy to Test -  Because functions are predictable and don’t have side effects, it’s easier to test them. You can test each function individually, knowing exactly what to expect.