# Solving a Coding Problem with Snap!: Negating Non-Negative Numbers

## How can we use Snap! to solve a problem involving negating non-negative numbers?

What is the task given? What are the specific requirements for solving it?

## Solution: Using Higher-Order Functions in Snap!

The problem can be solved by creating a block in Snap! using higher-order functions to negate non-negative integers.

To address the given coding problem effectively, we need to understand the requirements and constraints involved. The task involves creating a block, named 'processor', in Snap! that will process a list of integers by negating the non-negative numbers and then calculating their sum.

To achieve this, we can utilize higher-order functions (HOFs) in Snap! Higher-order functions are functions that operate on other functions by taking them as arguments. In this case, we can use higher-order functions such as 'map' or 'filter' to manipulate the list of integers without using traditional iteration methods.

When implementing the 'processor' block, we need to consider using recursion instead of loops to avoid violating the constraints of the task. Recursion allows a function to call itself repeatedly until a certain condition is met.

Here are the general steps to solve the problem using Snap!:

**1. Define the 'processor' block:**

Create a function named 'processor' that takes a list of integers as input.

**2. Use a higher-order function to negate non-negative numbers:**

Apply a higher-order function to the list to identify and negate the non-negative integers.

**3. Implement recursion:**

Recursively process the list by checking each element. If the element is non-negative, negate it and add it to the result of a recursive call with the rest of the list. If it's negative, proceed with the recursive call without negating the element.

**4. Calculate the sum:**

Sum up the negated non-negative numbers to obtain the final result.

By following these steps and leveraging the features of Snap!, you can effectively solve the coding problem involving negating non-negative numbers without using traditional iteration methods.