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Chap-7

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.

damian-lott
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Chap-7

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  1. Chap-7 Robust_Input

  2. 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

  3. Specification for Robust Input PACKAGE Robust_Input IS -------------------------------------------------------------- --| Package for getting numeric input robustly. --------------------------------------------------------------

  4. 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;

  5. 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;

  6. 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;

  7. 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;

  8. 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;

  9. The Body of Robust_Input WITH 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

  10. 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

  11. 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;

  12. 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

  13. 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

  14. 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;

  15. 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;

  16. 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;

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