Ordering

In this code challenge we create a program that sort a list of integers into ascending or descending order.

Problem

Create a program that allows entry of 10 numbers and then sorts them into ascending or descending order, based on user input

Extension problems

1. The user can input a word or string, and it arranges the string into alphabetical order. E.g. My Rabbit would be shown as “abbimty “. (Punctuation placement is not essential)
2. Repeat Extension 1, but include the sentence structure

Solution

Many languages have built-in sorting libraries or methods, such as with Python which has a sorted() function to sort lists easily. However, some languages do not have these features, and so, the pseudocode here uses a very simple algorithm to sort into descending and ascending order. The algorithm loops over the list, gets the biggest number in the list, removes it from the list, and adds it to a new list. Since the biggest number is removed everytime, we will get the next biggest number on every loop through the list. Adding the biggest to a new list would mean the biggest numbers are first in the list and the smallest are last.

NOTE: for ascending this is the same but with the smallest number everytime instead of the biggest.

So to get started, we create and empty list to store our ten numbers then get an input 10 times and add each number to our list of numbers. These will be the numbers we are going to sort.

numbers = EMPTY LIST

LOOP 10 TIMES
    number = INPUT
    ADD number TO numbers
END

Next, we are going to sort these numbers into descending order. We do this by looping 10 times. Getting the biggest number every loop, adding the number to our list descending_numbers and removing this number from numbers.

descending_numbers = EMPTY_LIST
LOOP 10 TIMES
    biggest = GET BIGGEST IN numbers
    ADD biggest TO descending_numbers
    REMOVE biggest FROM numbers
END

Below is the same code but for ascending order. This code is exactly the same but we need to get the smallest instead of the biggest.

ascending_numbers = EMPTY_LIST
LOOP 10 TIMES
    smallest = GET SMALLEST IN numbers
    ADD smallest TO descending_numbers
    REMOVE smallest FROM numbers
END

Finally, we can output the new sorted lists to the user.

OUTPUT descending_numbers
OUTPUT ascending_numbers