初步完成第四章lecture

lecture/src/Hight_order_fun.java

@@ -0,0 +1,7 @@
+/**
+ * @author Li Zezhong
+ * @create 2021-12-16 19:07
+ */
+public interface Hight_order_fun {
+    public int apply(int x);
+}

lecture/src/Ourcomparable.java

@@ -0,0 +1,7 @@
+/**
+ * @author Li Zezhong
+ * @create 2021-12-17 14:28
+ */
+public interface Ourcomparable<Item> {
+    public int compareTo(Item o);
+}

lecture/src/lecture2_1.java

@@ -2,6 +2,7 @@
  * @author Li Zezhong
  * @create 2021-12-03 20:28
  */
+
 public class lecture2_1 {
     public static void main(String[] args) {
         //正向构建List

lecture/src/lecture4_2.java

@@ -10,7 +10,8 @@ public static void main(String[] args) {
         n.addLast("c");
         n.rotateRight();
 
-//        VengefulSLList <String> n = new VengefulSLList<>(null);
+        System.out.println(do_twice(new Tenx(),2));
+        VengefulSLList <String> f =  (VengefulSLList <String>) new SList<String>(null);
 //        n.addLast("a");
 //        n.addLast("d");
 //        n.addLast("b");
@@ -20,6 +21,9 @@ public static void main(String[] args) {
 //        n.removeLast();
 //        n.print_deletedItems();
     }
+    public static int do_twice(Hight_order_fun f, int x){
+        return f.apply(f.apply(x));
+    }
 }
 
 class RotatingSLList<Item> extends SList<Item>{
@@ -49,5 +53,12 @@ public Item removeLast(){
     public void print_deletedItems(){
         deletedItems.positive_print();
     }
-
 }
+
+class Tenx implements Hight_order_fun{
+
+    @Override
+    public int apply(int x) {
+        return 10*x;
+    }
+}

lecture/src/lecture4_3.java

@@ -0,0 +1,66 @@
+import java.util.ArrayList;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * @author Li Zezhong
+ * @create 2021-12-16 16:30
+ */
+
+public class lecture4_3 {
+    public static void main(String[] args){
+        Dog[] dogs = new Dog[]{new Dog("Elyse", 3), new Dog("Sture", 9), new Dog("Benjamin", 15)};
+        max(dogs).bark();
+        Comparator<Dog> nc = Dog.getNameComparator();
+        System.out.println(nc.compare(dogs[0],dogs[2]));
+    }
+
+    public static Dog max(Dog[] items){
+        int maxDex = 0;
+        for (int i = 0; i < items.length; i += 1) {
+            int cmp = items[i].compareTo(items[maxDex]);
+            if (cmp > 0) {
+                maxDex = i;
+            }
+        }
+        return items[maxDex];
+    }
+
+    public static void getWords(String inputFileName){
+        List<String> lst = new ArrayList<String>();
+        In in = new In();
+
+    }
+}
+
+class Dog implements Comparable<Dog>{
+    private String name;
+    private int size;
+
+    public Dog(String n, int s) {
+        name = n;
+        size = s;
+    }
+
+    public void bark() {
+        System.out.println(name + " says: bark");
+    }
+
+    @Override
+    public int compareTo(Dog o) {
+        return this.size - o.size;
+    }
+
+    private static class NameComparator implements Comparator<Dog> {
+
+        @Override
+        public int compare(Dog o1, Dog o2) {
+            return o1.name.compareTo(o2.name);
+        }
+    }
+
+    public static Comparator<Dog> getNameComparator() {
+        return new NameComparator();
+    }
+}
+