chap-7 robust_input. a package for robust input read input values by calls to procedure get...
TRANSCRIPT
Chap-7
Robust_Input
A Package for Robust Input
• Read input values by calls to procedure Get
• overloading “Get” procedure for Integer and Float values
• There are 3 parameters for Get
• the first one to read item
• the second one for Min Value range
• the third one for Max Value range
Specification for Robust Input
PACKAGE Robust_Input IS-------------------------------------------------------
---------| Package for getting numeric input robustly.-------------------------------------------------------
-------
PROCEDURE Get (Item : OUT Integer; MinVal : IN Integer; MaxVal : IN Integer); -- Gets an integer value in the range MinVal..MaxVal -- Pre: MinVal and MaxVal are defined -- Post: MinVal <= Item <= MaxVal
PROCEDURE Get (Item : OUT Float; MinVal : IN Float; MaxVal : IN Float); -- Gets a float value in the range MinVal..MaxVal -- Pre: MinVal and MaxVal are defined -- Post: MinVal <= Item <= MaxVal
END Robust_Input;
Body of Robust Input
• PROCEDURE Get (Item : OUT Integer;• MinVal : IN Integer;• MaxVal : IN Integer) IS
• Declare SUBTYPE in the RANGE MinVal..MaxVal;
• Declare local variables• BEGIN -- Get
• END Get;
• PROCEDURE Get (Item : OUT Integer;• MinVal : IN Integer;• MaxVal : IN Integer) IS
• Declare SUBTYPE in the RANGE MinVal..MaxVal;• Declare local variables• BEGIN -- Get• LOOP• BEGIN --- Exception Handler Block • END -- Exception Handler Block• END LOOP;• END Get;
• PROCEDURE Get (Item : OUT Integer;• MinVal : IN Integer;• MaxVal : IN Integer) IS
• Declare SUBTYPE in the RANGE MinVal..MaxVal;• Declare local variables• BEGIN -- Get• LOOP• BEGIN -- exception handler block Sequence of statements for reading EXIT Exception Handling• END; -- exception handler block• END LOOP;• END Get;
• PROCEDURE Get (Item : OUT Integer;• MinVal : IN Integer;• MaxVal : IN Integer) IS
• Declare SUBTYPE in the RANGE MinVal..MaxVal;• Declare local variables• BEGIN -- Get• LOOP• BEGIN -- exception handler block• Sequence of statements to read• EXIT; -- valid data• EXCEPTION -- invalid data• WHEN condition =>• WHEN condition =>• END; -- exception handler block• END LOOP;• END Get;
The Body of Robust_InputWITH Ada.Text_IO;WITH Ada.Integer_Text_IO;WITH Ada.Float_Text_IO;PACKAGE BODY Robust_Input IS----------------------------------------------------------------| Body of package for robust numeric input handling--------------------------------------------------------------
PROCEDURE Get (Item : OUT Integer; MinVal : IN Integer; MaxVal : IN Integer) IS
SUBTYPE TempType IS Integer RANGE MinVal..MaxVal; TempItem : TempType; -- temporary copy of Item
BEGIN -- Get
LOOP BEGIN -- exception handler block Ada.Text_IO.Put(Item => "Enter an integer between
"); Ada.Integer_Text_IO.Put(Item => MinVal, Width => 0); Ada.Text_IO.Put(Item => " and "); Ada.Integer_Text_IO.Put(Item => MaxVal, Width => 0); Ada.Text_IO.Put(Item => " > "); Ada.Integer_Text_IO.Get(Item => TempItem); Item := TempItem; EXIT; -- valid data
EXCEPTION -- invalid data WHEN Constraint_Error => Ada.Text_IO.Put (Item => "Value is out of range. Please try again."); Ada.Text_IO.New_Line; Ada.Text_IO.Skip_Line; WHEN Ada.Text_IO.Data_Error => Ada.Text_IO.Put (Item => "Value is not an integer. Please try again."); Ada.Text_IO.New_Line; Ada.Text_IO.Skip_Line; END; -- exception handler block END LOOP;
END Get;
PROCEDURE Get (Item : OUT Float; MinVal : IN Float; MaxVal : IN Float) IS
SUBTYPE TempType IS Float RANGE MinVal..MaxVal; TempItem : TempType; -- temporary copy of Item
BEGIN -- Get
LOOP BEGIN -- exception handler block Ada.Text_IO.Put (Item => "Enter a floating-point value between "); Ada.Float_Text_IO.Put (Item => MinVal, Fore=> 1, Aft => 2, Exp => 0); Ada.Text_IO.Put(Item => " and "); Ada.Float_Text_IO.Put (Item => MaxVal, Fore=> 1, Aft => 2, Exp => 0); Ada.Text_IO.Put(Item => " > "); Ada.Float_Text_IO.Get(Item => TempItem); Item := TempItem; EXIT; -- valid data
EXCEPTION -- invalid data WHEN Constraint_Error => Ada.Text_IO.Put (Item => "Value is out of range. Please try again."); Ada.Text_IO.New_Line; Ada.Text_IO.Skip_Line; WHEN Ada.Text_IO.Data_Error => Ada.Text_IO.Put (Item => "Value is not floating point. Please try again."); Ada.Text_IO.New_Line; Ada.Text_IO.Skip_Line; END; -- exception handler block END LOOP;
END Get;
END Robust_Input;
A Program that use Robust_Input
WITH Robust_Input;PROCEDURE Test_Robust_Input IS-----------------------------------------------------------
-----| Demonstrates Robust_Input package-----------------------------------------------------------
---
SUBTYPE SmallInt IS Integer RANGE -10 ..10; SUBTYPE LargerInt IS Integer RANGE -100..100; SUBTYPE SmallFloat IS Float RANGE -10.0 ..10.0; SUBTYPE LargerFloat IS Float RANGE -100.0..100.0;
Small : SmallInt; SmallF : SmallFloat; Larger : LargerInt; LargerF : LargerFloat;
BEGIN -- Test_Robust_Input
Robust_Input.Get(Small,SmallInt'First,SmallInt'Last); Robust_Input.Get(Larger,LargerInt'First,LargerInt'Last); Robust_Input.Get(SmallF,SmallFloat'First,SmallFloat'Last); Robust_Input.Get(LargerF,LargerFloat'First,LargerFloat'Last);
END Test_Robust_Input;