Index: iknow-api/Services/Interfaces/IProfService.cs
===================================================================
--- iknow-api/Services/Interfaces/IProfService.cs	(revision ea405569ef29f56fbfc4d77708b6b3faf9286097)
+++ iknow-api/Services/Interfaces/IProfService.cs	(revision ea405569ef29f56fbfc4d77708b6b3faf9286097)
@@ -0,0 +1,18 @@
+using iknow_api.DTOs;
+
+namespace iknow_api.Services
+{
+    public enum GradeAction
+    {
+        Add,
+        Edit,
+        Remove
+    }
+
+    public interface IProfService
+    {
+        Task<List<SubjectStudentsDto>> GetStudentsBySubjectAsync(int professorId);
+
+        Task<GradeResultDto> SetGradeAsync(int professorId, GradeRequestDto request, GradeAction action);
+    }
+}