Records and sorting

This is a simple example of using arrays to store values, sort, check for
duplicates and display result in formatted form. 
------------------------------------------------------

with Ada.Text_Io;
with Ada.Integer_Text_Io;
use Ada.Text_Io;
use Ada.Integer_Text_Io;

procedure Studentlist is 

-------------------------Samir---------------------------------------------
   subtype Nametype is String(1..30);
   subtype Idtype is Natural range 0..99999;
   subtype Extensiontype is Natural range 0..9999;
---------------------------------------------------------------------------

   type Studentrecord is 
      record 
         Name      : Nametype      := (others => ' ');  
         Id        : Idtype;  
         Extension : Extensiontype;  
      end record; 
---------------------------------------------------------------------------

   subtype Studentindex is Integer range 1..100;
   type Studentarraytype is array (Studentindex) of Studentrecord; 

---------------------------------------------------------------------------

   Studentlist    : Studentarraytype;      -- our array of students    
   Currentindex   : Natural := 0; 
   -- the index to the current array item 
   Currentstudent : Studentrecord;         -- the current student 
   Countrecords   : Integer          := 0;  

   Length : Integer := 0;  
   
   

   -- Specification of input procedure.  You are to write the body.  
   procedure Getstudent (Item : in out Studentrecord) is 
      
      
      
   begin -- GetStudent      

      Item.Name := (Others => ' ');
      
      Ada.Text_Io.Put("GetStudent() Please enter Student ID: ");
      Get(Item.Id);
      Skip_Line;

      Put("Please enter student Name: ");
      Get_Line(Item.Name,Length);

      Put("Please enter Extension: ");
      Get(Item.Extension);
      Skip_Line;
      New_Line;
   end Getstudent;

-------------------------------------------------------------   

   -- Procedure for swapping
   procedure Swap (X,Y : in out StudentRecord) is 

      Temp : StudentRecord;  

   begin -- Swap

      Temp := X;
      X := Y;
      Y := Temp;
   end Swap;

--------------------------------------------------------------------------
   -- Procedure for sorting the students by name

   procedure Selectionsort (Studentarray : in out Studentarraytype; 
                            Arraysize : in Integer) is 

      Indexofmin : Integer;  


   begin

      for Positiontofill in 1 .. Arraysize-1 loop

         Indexofmin := Positiontofill;

         for Itemtocompare in Positiontofill+1 .. Arraysize loop

            if Studentarray(Itemtocompare).Name <
Studentarray(Indexofmin).
                  Name then

               Indexofmin := Itemtocompare;
            end if;

         end loop;

         if Indexofmin /= Positiontofill then

            Swap(Studentarray(Positiontofill),Studentarray(
                  Indexofmin));
         end if;

      end loop;

   end Selectionsort;

---------------------------------------------------------------------------

CurrentI : Integer := 0;


begin -- StudentList
   Put_Line(Item => "Welcome to the Student Information Program.");
      
   loop
   
      
      -- Get the next student
      GetStudent(CurrentStudent);
      
      -- Sentiniel that tells the loop to exit
      -- when the ID number is zero
      exit when Currentstudent.Id = 0;
        
       -- LocalLoopCounter  
       
            -- Loop that checks the current id with all the IDs
            -- in the array to find duplicates
            CurrentI := 0;
            for I in 1..CurrentIndex loop
                  
               If StudentList(I).ID = CurrentStudent.ID then
                                                               
                     CurrentI := I;
                     
                end if;
                
            end loop;       
         
         If CurrentI = 0 then
             CurrentIndex := CurrentIndex + 1;
             StudentList(CurrentIndex) := CurrentStudent;       
                  

         else
         
            StudentList(CurrentI) := CurrentStudent;
            
         end if;
         
              
   end loop;
   
---------------------------------------------------------------------------

   -- Output the header for the nicely formatted output.  
   Put("NAME                                  ID        EXTENSION");
   New_Line;
   Put("---------------------------------------------------------");
   New_Line;

---------------------------------------------------------------------------
   
   Selectionsort(Studentarray => Studentlist, Arraysize=>
Currentindex);
   
      -- Loop for outputting all the student records stored in the array
   
      while CurrentIndex /= CountRecords loop

            Countrecords := Countrecords + 1;
             
            Put(Studentlist(Countrecords).Name);
            Put(Studentlist(Countrecords).Id);
            Put(Studentlist(Countrecords).Extension);
           
            New_Line;
         
   end loop;

end Studentlist;