---------------------------
-- Math Package
-- October 18, 2002
-- Malia Kilpinen
-- 16.35 Problem Set 2 Example Solution
---------------------------

with Math_Functions;
use Math_Functions;

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


procedure Menu is

   -- declare and initialize variables

   Continue_Loop    : Integer;        -- variable used for continuing loop
   Menu_Selection   : Integer;
   Number           : Integer := - 1;
   Factorial_Answer : Integer := 0;
   Inputfloat1      : Float;
   Inputfloat2      : Float;
   Maximum_Answer   : Float;
   Inputinteger1    : Integer;
   Inputinteger2    : Integer;
   Sum_Answer       : Integer;


begin

   Continue_Loop := 1;

   while Continue_Loop=1 loop
      loop -- for exceptions
         begin --exception block

            -- Display Menu Options
            Ada.Text_Io.New_Line;
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("*******************Menu*******************");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("Select a math function:");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("1)  n!");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("2)  max of two floats");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("3)  add two integers");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("4)  exit program");
            Ada.Text_Io.New_Line;
            Ada.Text_Io.Put ("Enter selection number:   ");

            -- Get user input
            Ada.Integer_Text_Io.Get(
                                    Item  => Menu_Selection,
                                    Width => 10);
            Ada.Text_Io.Skip_Line; -- in case, input is invalid.  clear buffer.

            -- Determine if the user input is a valid integer
            while Menu_Selection <1 or Menu_Selection >4 loop
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Invalid input");
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Select option 1, 2, 3, or 4");
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Reenter selection number:   ");
               Ada.Integer_Text_Io.Get(Menu_Selection, Width=>10);
               Ada.Text_Io.Skip_Line; -- in case, input is invalid.  clear buffer.
            end loop;


            -- Perform menu functions
            -- This can be implemented in several ways...  this is just an example
            -- using if statements.  A case statement could be used easily.

            ------- Option 1 --------
            -- N!
            if Menu_Selection = 1 then

               while Number<0 loop
                  -- 1) Prompt user for integer
                  Ada.Text_Io.New_Line;
                  Ada.Text_Io.Put("N! function");
                  Ada.Text_Io.New_Line;
                  Ada.Text_Io.Put("Enter N as an integer: ");

                  -- 2) Get user input
                  Ada.Integer_Text_Io.Get(Number, Width=>5);
                  Ada.Text_Io.Skip_Line;

                  -- 3) Error check
                  if Number<0 then
                     Ada.Text_Io.New_Line;
                     Ada.Text_Io.Put("You must enter an integer >= 0");
                     Ada.Text_Io.New_Line;
                  end if;
               end loop;

               -- 4) Call function
               Factorial_Answer:= N_Factorial(N => Number);

               -- 5) Print answer to screen
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("The answer is: ");
               Ada.Integer_Text_Io.Put(
                                       Item  => Factorial_Answer,
                                       Width => 15);
               -- end of n! function, will loop back to main menu


               ------- Option 2 --------
               -- Max Value
            elsif Menu_Selection=2 then

               -- 1) Prompt/get user for two float inputs
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Enter first float:");
               Ada.Float_Text_Io.Get(Inputfloat1, Width=>15);
               Ada.Text_Io.Skip_Line;
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Enter second float:");
               Ada.Float_Text_Io.Get(Inputfloat2, Width=>15);
               Ada.Text_Io.Skip_Line;

               -- 2) Call function
               Maximum_Answer := Max_Value(
                                           Num1 => Inputfloat1,
                                           Num2 => Inputfloat2);

               -- 3) Print answer screen
               Ada.Text_Io.Put("The maximum value is: ");
               Ada.Float_Text_Io.Put(
                                     Item => Maximum_Answer,
                                     Fore => 15,
                                     Aft  => 3,
                                     Exp  => 0);
               -- end of max value function, will loop back to main menu


               ------- Option 3 --------
               -- Add two integers
            elsif Menu_Selection=3 then

               -- 1) Prompt/get user for integer inputs
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Enter first integer value:   ");
               Ada.Integer_Text_Io.Get(Inputinteger1, Width=>10);
               Ada.Text_Io.Skip_Line;
               Ada.Text_Io.Put("Enter second integer value:  ");
               Ada.Integer_Text_Io.Get(Inputinteger2, Width=>10);
               Ada.Text_Io.Skip_Line;

               -- 2) Call function
               Sum_Answer := Add_Integers(
                                          Num1 => Inputinteger1,
                                          Num2 => Inputinteger2);

               -- 3) Print answer to screen
               Ada.Text_Io.Put("The sum is: ");
               Ada.Integer_Text_Io.Put(
                                       Item  => Sum_Answer,
                                       Width => 15);
               Ada.Text_Io.New_Line;
               -- end of sum function


               ------- Option 4 --------
               -- Exit loop
            elsif Menu_Selection=4 then
               Continue_Loop := 0;
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Exiting...");
               Ada.Text_Io.New_Line;
               exit;
            end if;

            -- Do exception handling.  Determine if user input is of correct type.
            -- Example:  If a float is inputed instead of an int.
         exception
            when Ada.Text_Io.Data_Error =>
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Data input is not the correct type.");
               Ada.Text_Io.Skip_Line;   -- clear input buffer
               Ada.Text_Io.New_Line;
            when Constraint_Error =>
               Ada.Text_Io.New_Line;
               Ada.Text_Io.Put("Constraint error.  Data overflow.");
               Ada.Text_Io.Skip_Line;   -- clear input buffer
               Ada.Text_Io.New_Line;
         end;
         -- end of exception block

      end loop;
      -- end of loop for exceptions

   end loop;
   -- end of menu loop

   Ada.Text_Io.New_Line;
   Ada.Text_Io.Put("End of program!");

   end Menu;