feat: update structure

cs2030s/labs/Lab7/Test5.java

@@ -0,0 +1,72 @@
+import cs2030s.fp.Immutator;
+import cs2030s.fp.Combiner;
+import cs2030s.fp.Memo;
+
+public class Test5 {
+  public static void main(String[] args) {
+    CS2030STest we = new CS2030STest();
+    
+    class A {
+      private int x;
+      public A(int x) {
+        this.x = x;
+      }
+      public int getX() {
+        return this.x;
+      }
+      @Override
+      public String toString() {
+        return "A:" + this.x;
+      }
+    }
+    class B extends A {
+      public B(int x) {
+        super(x);
+      }
+      @Override
+      public String toString() {
+        return "B:" + super.toString();
+      }
+    }
+    class C extends B {
+      public C(int x) {
+        super(x);
+      }
+      @Override
+      public String toString() {
+        return "C:" + super.toString();
+      }
+    }
+    
+    Immutator<C, A> incr = x -> new C(x.getX() + 1);
+    Combiner<C, A, A> fib = (x, y) -> new C(x.getX() + y.getX());
+    Immutator<MemoList<B>, A> dbl  = x -> MemoList.generate(x.getX(), new C(x.getX()), y -> new C(y.getX() + 1));
+    MemoList<B> bList1 = MemoList.generate(8, new C(0), incr);
+    we.expect(
+      "PECS is followed on generate (Immutator)",
+      bList1.toString(),
+      "[C:B:A:0, ?, ?, ?, ?, ?, ?, ?]"
+    );
+    
+    MemoList<B> bList2 = MemoList.generate(8, new C(0), new C(1), fib);
+    we.expect(
+      "PECS is followed on generate (Combiner)",
+      bList2.toString(),
+      "[C:B:A:0, C:B:A:1, ?, ?, ?, ?, ?, ?]"
+    );
+    
+    MemoList<B> bList3 = bList1.map(incr);
+    we.expect(
+      "PECS is followed on map",
+      bList3.toString(),
+      "[?, ?, ?, ?, ?, ?, ?, ?]"
+    );
+    
+    MemoList<B> bList4 = bList1.flatMap(dbl);
+    we.expect(
+      "PECS is followed on flatMap",
+      bList4.toString(),
+      "[C:B:A:1, C:B:A:2, ?, C:B:A:3, ?, ?, C:B:A:4, ?, ?, ?, C:B:A:5, ?, ?, ?, ?, C:B:A:6, ?, ?, ?, ?, ?, C:B:A:7, ?, ?, ?, ?, ?, ?]"
+    );
+  }
+}