HoistingCrane/HoistingCrane/CollectionGenericObjects/AbstractCompany.cs

@@ -41,9 +41,9 @@ namespace HoistingCrane.CollectionGenericObjects
             arr.SetMaxCount = GetMaxCount;
         }
 
-        public static int operator +(AbstractCompany company, DrawningTrackedVehicle car)
+        public static DrawningTrackedVehicle operator +(AbstractCompany company, DrawningTrackedVehicle car)
         {
-            return company.arr?.Insert(car) ?? -1;
+            return company.arr?.Insert(car) ?? null;
         }
         public static DrawningTrackedVehicle operator -(AbstractCompany company, int position)
         {

HoistingCrane/HoistingCrane/CollectionGenericObjects/ICollectionGenericObjects.cs

@@ -16,14 +16,14 @@
         /// </summary>
         /// <param name="obj"></param>
         /// <returns></returns>
-        int Insert(T obj);
+        T? Insert(T obj);
         /// <summary>
         /// Добавление элемента в коллекцию на определенную позицию
         /// </summary>
         /// <param name="obj"></param>
         /// <param name="position"></param>
         /// <returns></returns>
-        int Insert(T obj, int position);
+        T? Insert(T obj, int position);
         /// <summary>
         /// Удаление элемента из коллекции по его позиции
         /// </summary>

HoistingCrane/HoistingCrane/CollectionGenericObjects/MassivGenericObjects.cs

@@ -30,7 +30,7 @@
             return null;  
         }
 
-        public int Insert(T obj)
+        public T? Insert(T obj)
         {
             for (int i = 0; i < Count; i++)
             {
@@ -39,34 +39,34 @@
                     return Insert(obj, 0);
                 } 
             }
-            return -1;
+            return null;
         }
 
-        public int Insert(T obj, int position)
+        public T? Insert(T obj, int position)
         {
             //todo Проверка позиции
             if (position < 0 || position > Count)
             {
-                return -1;
+                return null;
             }
 
             if (arr[position] == null)
             {
                 arr[position] = obj;
-                return position;
+                return arr[position];
             }
             else
             {
                 if (Insert(obj, position + 1) != null)
                 {
-                    return position;
+                    return arr[position + 1];
                 }
                 if (Insert(obj, position - 1) != null)
                 {
-                    return position;
+                    return arr[position - 1];
                 }
             }
-            return -1;
+            return null;
         } 
 
         public T? Remove(int position)

HoistingCrane/HoistingCrane/FormCarCollection.cs

@@ -38,7 +38,7 @@ namespace HoistingCrane
                 default:
                     return;
             }
-            if ((_company + drawning) != -1)
+            if ((_company + drawning) != null)
             {
                 MessageBox.Show("Объект добавлен");
                 pictureBox.Image = _company.Show();