added old projects

CS101/lab_11/.vscode/settings.json

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

CS101/lab_11/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_11/src/Tester.java

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+public class Tester {
+    public static void main(String[] args) throws Exception {
+        //System.out.println("Hello, World!");
+        //System.out.println(Utilities.ceiling(-1.2));
+        //System.out.println(Utilities.ceiling(3));
+        //System.out.println(Utilities.ceiling(1.6));
+        System.out.println(Utilities.stars(5));
+    }
+}

CS101/lab_11/src/Utilities.java

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+import java.math.BigInteger;
+
+public class Utilities {
+    
+    public static int abs(int num) {
+        if (num < 0) 
+            num *= -1;
+        return num;
+    }
+
+    public static int ceiling(double num) {
+        double x = num % 1;
+        if (x < .5)
+            num -= x;
+        else if (x >= .5)
+            num += x;
+        return (int) num;
+    }
+
+    public static BigInteger fact(int x) {
+        BigInteger fact = new BigInteger("1");
+
+        for (int i = 2; i <= x; i++)
+            fact = fact.multiply(BigInteger.valueOf(i));
+        
+        return fact;
+    }
+
+    public static String stars(int x) {
+        String s = "";
+        
+        for (int i = 1; i <= x; ++i) {
+            for (int j = 1; j <= i; ++j) {
+                s += "*";
+            }
+            s += " ";
+        }
+            return s;
+    }
+}