added old projects

CS101/lab_13/.vscode/settings.json

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+{
+    "java.project.sourcePaths": ["src"],
+    "java.project.outputPath": "bin"
+}

CS101/lab_13/README.md

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+## Getting Started
+
+Welcome to the VS Code Java world. Here is a guideline to help you get started to write Java code in Visual Studio Code.
+
+## Folder Structure
+
+The workspace contains two folders by default, where:
+
+- `src`: the folder to maintain sources
+- `lib`: the folder to maintain dependencies
+
+Meanwhile, the compiled output files will be generated in the `bin` folder by default.
+
+> If you want to customize the folder structure, open `.vscode/settings.json` and update the related settings there.
+
+## Dependency Management
+
+The `JAVA PROJECTS` view allows you to manage your dependencies. More details can be found [here](https://github.com/microsoft/vscode-java-dependency#manage-dependencies).

CS101/lab_13/src/RomanNumeralCalculator.java

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+import java.util.Scanner;
+
+public class RomanNumeralCalculator {
+    public static void main(String[] args) {
+        Scanner input = new Scanner(System.in);
+        int num;
+
+        do {
+            System.out.println("Please enter an integer from 1 to 5999. Enter a negative number or 0 to exit."); //can also exit on 0
+            System.out.print("-> ");
+            num = input.nextInt();
+
+            if (num <= 0)
+                System.exit(0);
+
+            if (num < 6000) {
+                String roman = "";
+
+                while (num >= 1000) {
+                    roman += "M";
+                    num -= 1000;
+                }
+
+                switch (num / 100) { //Needed to switch from modulus division
+                case 0:
+                case 1:
+                case 2:
+                case 3:
+                    break;
+                case 4:
+                    roman += "CD";
+                    num -= 400;
+                    break;
+                case 5:
+                case 6:
+                case 7:
+                case 8:
+                    roman += "D";
+                    num -= 500;
+                    break;
+                case 9:
+                    roman += "CM";
+                    num -= 900;
+                    break;
+                default:
+                    System.err.println("There is a problem with the hundreds place."); // not tens place
+                }
+
+                while (num >= 100) {
+                    roman += "C";
+                    num -= 100;
+                }
+
+                int x = num / 10 % 10;
+                switch (num / 10 % 10) {
+                    case 0:
+                    case 1:
+                    case 2:
+                    case 3:
+                        break;
+                    case 4:
+                        roman += "XL";
+                        num -= 40;
+                        break;
+                    case 5:
+                    case 6:
+                    case 7:
+                    case 8:
+                        roman += "L";
+                        num -= 50;
+                        break;
+                    case 9:
+                        roman += "XC"; //X & C were flipped
+                        num -= 90;
+                        break;
+                    default:
+                        System.err.println("There is a problem with the tens place.");
+                }
+
+                while (num >= 10) {
+                    roman += "X";
+                    num -= 10;
+                }
+
+                switch (num) {
+                    case 0:
+                    case 1:
+                    case 2:
+                    case 3:
+                        break;
+                    case 4:
+                        roman += "IV";
+                        num -= 4;
+                        break;
+                    case 5:
+                    case 6:
+                    case 7:
+                    case 8:
+                        roman += "V"; //Needed capital 'V'
+                        num -= 5;
+                        break;
+                    case 9:
+                        roman += "IX";
+                        num -= 9;
+                        break;
+
+                    default:
+                        System.err.println("There is a problem with the units place.");
+                }
+
+                while (num > 0) {
+                    roman += "I";
+                    num--;
+                }
+
+                System.out.println(roman);
+            }
+        } while (true); // Would not loop < was facing the wrong way
+    }
+}