Unit four, section one

Unit four, section one#

Introduction to high level programming

Challenge work submission#

  1. Read chapter nine of the textbook.

  2. Complete challenge work #6, on page 467 of the text.

Note

Corresponds to challenge work #6, on page 467 of the text. The instructions may say a short profile, but the course Brightspace says 2-3 paragraphs is sufficient.

Version control#

Version control and version control software (vcs) is essential to software developers. With it, we can track changes and collaborate without exclusive checkout or the risk of overwriting files. Like most software, there are different options available. One of the most popular and commonly known is git. Git is a distributed vcs, which means that unlike centralized systems, it can operate locally and allow for offline access to projects, with faster computational operations.

Unlike word processors which may rely on shared drives for collaboration, git provides a branching system which allows us to create a new branch for a feature or patch. When paired with other tools on the market, git becomes integrated into a community, an IDE, or developer tools. GitHub, Bitbucket, and GitLab are some of the most popular choices, though others exist.

A downside of version control software is the learning curve. Unlike a traditional text editor, there are commands which may often need to be run from the terminal. These commands require a new way of thinking for those who are not familiar with the operations, including initialize, push, pull, commit, merge, rebase, and cherry picking.

Despite the complexities, it’s an invaluable tool to a modern developer. As an example of the general usefulness, the static site and my source documentation for CS200 is being maintained on GitHub using Git.

Works cited#

Schneider, G. Michael, and Judith Gersting. Invitation to Computer Science. 6th ed., Cengage Learning, 2013.

Git Documentation. Git-SCM, https://git-scm.com/docs. Accessed 9 Feb. 2025.

“What is Git?” GitHub Guides, git-guides. Accessed 9 Feb. 2025.

Assignment 4 (chapter four, section one)#

  1. Again create a data file of random integers. Then write a program in the language of your choice to implement the selection sort algorithm of Figure 3.6 using file input data. Write a separate function (method, procedure) to find the location of the largest number in the unsorted section of the list (see Figure 2.14) and have your main function call that as needed. Write your sorted list to another data file.

Psuedocode#

I chose this answer to revisit a similar question that I approached in an earlier unit, with a newfound understanding of what’s happening under the hood. The psuedo has been simplified from my earlier approach, and I again chose javascript (my most natural language).

Note

  1. create a .txt file with random ints

  2. run the selection sort algorithm against it, similar to unit 1 section 3

  3. use a helper function to find the largest int in the sort

  4. re-write the sort data to another .txt file

This selection sort solution is a time complexity of O(n^2), which is inefficient for large tasks but fine for this small educational task. In a larger production, I would use something with better performance like a merge sort or quick sort.

Program#

const fs = require('fs');

//make .txt file with ran ints
function createRandomInts(fileName, count, min, max) {
   const data = Array.from({ length: count }, () => Math.floor(Math.random() * (max - min + 1)) + min);
   fs.writeFileSync(fileName, data.join('\n'), 'utf8');
}

//helper func to find largest in .txt
function findLargest(arr, end) {
   let largestPosition = 0;
   for (let i = 1; i <= end; i++) {
      if (arr[i] > arr[largestPosition]) {
            largestPosition = i;
      }
   }
   return largestPosition;
}

//run sort
function selectionSort(arr) {
   const n = arr.length;
   for (let i = n - 1; i > 0; i--) {
      const largestPosition = findLargest(arr, i);
      // Swap the largest element with the last unsorted element
      [arr[i], arr[largestPosition]] = [arr[largestPosition], arr[i]];
   }
   return arr;
}

//read, then write out to another file
function sortDataFile(inputFile, outputFile) {
   const data = fs.readFileSync(inputFile, 'utf8').split('\n').map(Number);
   const sortedData = selectionSort(data);
   fs.writeFileSync(outputFile, sortedData.join('\n'), 'utf8');
}

const inputFileName = 'input.txt';
const outputFileName = 'output.txt';

createRandomInts(inputFileName, 100, 1, 1000); // # of ints, range low, range max
sortDataFile(inputFileName, outputFileName);

console.log(`Sort completed. Open "${outputFileName}" for data.`);

Works cited#

Schneider, G. Michael, and Judith Gersting. Invitation to Computer Science. 6th ed., Cengage Learning, 2013.

“Mozilla Developer Docs, Math Functions.” MDN Web Docs, Mozilla, https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math. Accessed 25 Jan. 2025.

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