0002_Second push, added[add, insert(not working), remove, toString] for MyList, added[toString] for Pair, added[toString] for MyListElement

Main.java

@@ -0,0 +1,10 @@
+public class Main {
+    public static void main(String[] args) {
+        MyList list = new MyList();
+        list.add(new Pair(2,2));
+        list.remove(1);
+        list.insert(new Pair(3,3), 0);
+
+        System.out.println(list.toString());
+    }
+}

MyList.java

@@ -2,6 +2,69 @@ public class MyList {
     public MyListElement first;
 
     public MyList() {
-        first = new MyListElement();
+        first = null;
+    }
+
+    //Adds elem to list.
+    public void add(Pair pair) {
+        MyListElement elem = new MyListElement(pair, null);
+        //Case 1: List is empty
+        if (this.first == null) {
+            this.first = elem;
+        //Case 2: List is not empty
+        } else {
+            MyListElement node = this.first;
+            while (node.next != null) {
+                node = node.next;
+            }
+            node.next = elem;
+        }
+    }
+
+    //Inserts elem at index.
+    public void insert(Pair pair, int index) {
+        MyListElement node = this.first;
+        MyListElement pre = this.first;
+        if (index == 0) {
+            this.first = new MyListElement(pair, node);
+        } else {
+            int i = 1;
+            while ((index != i) && (node.next != null)) {
+                pre = node;
+                node = node.next;
+                i++;
+            }
+        }
+    }
+
+    //Removes element with key from list.
+    public void remove(Object key) {
+        //Case 1: Element to remove is first
+        if (this.first.data.key == key) {
+            this.first = this.first.next;
+        //Case 2: Element to remove is not first
+        } else {
+            MyListElement node = this.first;
+            MyListElement pre = this.first;
+            while ((node.next != null) && (node.data.key != key)) {
+                pre = node;
+                node = node.next;
+                if (node.data.key == key) {
+                    pre.next = node.next;
+                }
+            }
+        }
+    }
+
+    //Return MyList as String.
+    @Override
+    public String toString() {
+        String listAsString = "";
+        MyListElement node = this.first;
+        while (node != null) {
+            listAsString += (node.data.toString() + ", ");
+            node = node.next;
+        }
+        return listAsString;
     }
 }

MyListElement.java

@@ -11,4 +11,9 @@ public class MyListElement {
         this.data = data;
         this.next = next;
     }
+
+    @Override
+    public String toString() {
+        return this.data.toString();
+    }
 }

Pair.java

@@ -11,4 +11,9 @@ public class Pair {
         this.key = key;
         this.data = data;
     }
+
+    @Override
+    public String toString() {
+        return ("(" + this.key.toString() + "," + this.data.toString() + ")");
+    }
 }

sort_algorithms.java

@@ -0,0 +1,3 @@
+public class sort_algorithms {
+    
+}