|
Plus que n'importe quelle autre tâche, le traitement
de fichier est principalement dans le besoin de la manipulation d'exception.
Comme nous verrons dans la prochaine section, pandant le traitement de
fichier, il y a beaucoup de choses qui peuvent tourner mal. Pour cette
raison, la création et/ou la gestion des stream devraient être exécutées
dans un bloc try pour être prêtes pour manipuler les
exceptions qui se produiraient. En plus de manipuler réellement les exceptions,
le langage C# fournit un mot-clé spécial des
ressources libres utilisées. Ce mot-clé est finally.
Finalement le mot-clé est utilisé pour créer une
section d'une exception. Comme catch, le bloc finally ne peut
pas exister par lui-même. Il peut être créé après une section try. La formule utilisée serait :
try
{
}
finally
{
}
Basé sur ceci, la section finally a son
propre corps, délimité par ses accolades. Comme catch, la section finaly
est créée après la section try. À la différence que catch, n'a finalement
jamais de parenthèses et ne prend jamais des arguments. À la différence
de catch, la section finally est toujours exécutée.
Puisque la clause finally est toujours exécutée, vous
pouvez y inclure n'importe quel type de code mais il est
habituellement approprié de libérer les ressources qui ont été allouées
plus tôt. Voici un exemple :
using System;
using System.IO;
public class Program
{
static int Main(string[] args)
{
string NameOfFile = "Members.clb";
FileStream fstPersons = new FileStream(NameOfFile, FileMode.Create);
BinaryWriter wrtPersons = new BinaryWriter(fstPersons);
try
{
wrtPersons.Write("James Bloch");
wrtPersons.Write("Catherina Wallace");
wrtPersons.Write("Bruce Lamont");
wrtPersons.Write("Douglas Truth");
}
finally
{
wrtPersons.Close();
fstPersons.Close();
}
return 0;
}
}
De la même manière, vous pouvez employer
finalement une section pour libérer des ressources utilisées en lisant
d'un jet :
using System;
using System.IO;
public class Program
{
static int Main(string[] args)
{
/* string NameOfFile = "Members.clb";
FileStream fstPersons = new FileStream(NameOfFile, FileMode.Create);
BinaryWriter wrtPersons = new BinaryWriter(fstPersons);
try
{
wrtPersons.Write("James Bloch");
wrtPersons.Write("Catherina Wallace");
wrtPersons.Write("Bruce Lamont");
wrtPersons.Write("Douglas Truth");
}
finally
{
wrtPersons.Close();
fstPersons.Close();
}*/
string NameOfFile = "Members.clb";
string strLine = null;
FileStream fstMembers = new FileStream(NameOfFile, FileMode.Open);
BinaryReader rdrMembers = new BinaryReader(fstMembers);
try
{
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
}
finally
{
rdrMembers.Close();
fstMembers.Close();
}
return 0;
}
}
Naturellement, puisque la totalité du bloc de code
commence par une section try, il est utilisé pour la
manipulation d'exception. Ceci signifie que vous pouvez ajouter des
sections catch nécessaires et appropriées mais vous ne le devez
pas .
|
 Étude
pratique : Libérer enfin des ressources
|
|
- Commencez Microsoft Visual C# et créez une application de console
appelée IceCream4
- Sauvegardez le projet, sur la barre d'outils standard, cliquez le bouton
sauvegarder tout
- Changez le nom de solution en VendingMachine4
- Acceptez le nom du projet comme IceCream3 et cliquez Sauvegarder
- Pour créer une nouvelle classe, sur le menu principal, cliquez projet
- > Ajouter la classe…
- Placez le nom IceScream et cliquez Ajouter
- Changez le fichier comme suit :
using System;
using System.IO;
namespace IceCream4
{
delegate void Request();
// This class is used to create and manage an ice scream
// and to process an order
public sealed class IceCream
{
// This is the base price of an ice scream
// Optional values may be added to it
public const decimal BasePrice = 1.55M;
// These arrays are used to build the components
// of various ice creams
private string[] Flavor;
private string[] Container;
private string[] Ingredient;
// Additional factor used to process an ice scream order
private int Scoops;
private decimal TotalPrice;
// Variables that will hold the user's choice
// These are declared "globally" so they can be
// shared among methods
int ChoiceFlavor;
int ChoiceContainer;
int ChoiceIngredient;
// This default constructor is the best place for
// us to initialize the array
public IceCream()
{
Flavor = new string[10];
Flavor[0] = "Vanilla";
Flavor[1] = "Cream of Cocoa";
Flavor[2] = "Chocolate Chip";
Flavor[3] = "Organic Strawberry";
Flavor[4] = "Butter Pecan";
Flavor[5] = "Cherry Coke";
Flavor[6] = "Chocolate Brownies";
Flavor[7] = "Caramel Au Lait";
Flavor[8] = "Chunky Butter";
Flavor[9] = "Chocolate Cookie";
Ingredient = new string[4];
Ingredient[0] = "No Ingredient";
Ingredient[1] = "Peanuts";
Ingredient[2] = "M & M";
Ingredient[3] = "Cookies";
Container = new string[3];
Container[0] = "Cone";
Container[1] = "Cup";
Container[2] = "Bowl";
}
// This method requests a flavor from the user and
// returns the choice
public void ChooseFlavor()
{
// Make sure the user selects a valid number
//that represents a flavor...
do
{
// In case the user types a symbol that
// is not a number
try
{
Console.WriteLine("What type of flavor do you want?");
for (int i = 0; i < Flavor.Length; i++)
Console.WriteLine("{0} - {1}", i + 1, Flavor[i]);
Console.Write("Your Choice? ");
ChoiceFlavor = int.Parse(Console.ReadLine());
}
catch (FormatException) // display an appropriate message
{
Console.WriteLine("You must enter a valid number " +
"and no other character!");
}
// If the user typed an invalid number out of the
// allowed range
// let him or her know and provide another chance
if (ChoiceFlavor < 1 || ChoiceFlavor > Flavor.Length)
Console.WriteLine("Invalid Choice - Try Again!\n");
} while (ChoiceFlavor < 1 || ChoiceFlavor > Flavor.Length);
}
// This method allows the user to select a container
public void ChooseContainer()
{
// Make sure the user selects a valid number that
// represents a container
do
{
// If the user types a symbol that is not a number
try
{
Console.WriteLine("What type of container do you want?");
for (int i = 0; i < Container.Length; i++)
Console.WriteLine("{0} - {1}", i + 1, Container[i]);
Console.Write("Your Choice? ");
ChoiceContainer = int.Parse(Console.ReadLine());
}
catch (FormatException) // display an appropriate message
{
Console.WriteLine("You must enter a valid " +
"number and no other character!");
}
// If the user typed an invalid number out of the
// allowed range
// let him or her know and provide another chance
if ((ChoiceContainer < 1) ||
(ChoiceContainer > Container.Length))
Console.WriteLine("Invalid Choice - Try Again!");
} while ((ChoiceContainer < 1) ||
(ChoiceContainer > Container.Length));
}
public void ChooseIngredient()
{
do
{
try
{
Console.WriteLine("Do you want an ingredient or not");
for (int i = 0; i < Ingredient.Length; i++)
Console.WriteLine("{0} - {1}",
i + 1,
Ingredient[i]);
Console.Write("Your Choice? ");
ChoiceIngredient = int.Parse(Console.ReadLine());
}
catch (FormatException)
{
Console.WriteLine("You must enter a valid " +
"number and no other character!");
}
if ((ChoiceIngredient < 1) ||
(ChoiceIngredient > Ingredient.Length))
Console.WriteLine("Invalid Choice - Try Again!");
} while ((ChoiceIngredient < 1) ||
(ChoiceIngredient > Ingredient.Length));
}
public void SpecifyNumberOfScoops()
{
do
{
try
{
Console.Write("How many scoops(1, 2, or 3)? ");
Scoops = int.Parse(Console.ReadLine());
}
catch (FormatException)
{
Console.WriteLine("You must enter a valid number " +
"and no other character!");
}
if (Scoops < 1 || Scoops > 3)
Console.WriteLine("Invalid Choice - Try Again!");
} while (Scoops < 1 || Scoops > 3);
}
// This method is used to process a customer order
// It uses the values of the above methods
public void ProcessAnOrder()
{
// int ChoiceFlavor;
// int ChoiceContainer;
// int ChoiceIngredient;
decimal PriceIngredient, PriceScoop;
// Let the user know that this is a vending machine
Console.WriteLine("=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=");
Console.WriteLine("Ice Scream Vending Machine");
Console.WriteLine("-----------------------------------");
// Let the user select the components of the ice scream
Request Get = new Request(ChooseFlavor);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(ChooseContainer);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(ChooseIngredient);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(SpecifyNumberOfScoops);
Get();
Console.WriteLine("-----------------------------------");
// If the user selects an ingredient instead of "No Ingredient",
// add $0.50 to the order
if ((ChoiceIngredient == 2) ||
(ChoiceIngredient == 3) ||
(ChoiceIngredient == 4))
PriceIngredient = 0.50M;
else
PriceIngredient = 0.00M;
// Instead of multiplying a number scoops to a value,
// We will use an incremental value depending on
// the number of scoops
if (Scoops == 1)
PriceScoop = 0.65M;
else if (Scoops == 2)
PriceScoop = 1.05M;
else
PriceScoop = 1.55M;
// Calculate the total price of the ice scream
TotalPrice = BasePrice + PriceScoop + PriceIngredient;
// Create the ice scream...
// And display a receipt to the user
DisplayReceipt();
}
// This method is used to display a receipt to the user
public void DisplayReceipt()
{
Console.WriteLine("\n=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=");
Console.WriteLine("Ice Scream Order");
Console.WriteLine("-----------------------------------");
Console.WriteLine("Flavor: {0}",
Flavor[ChoiceFlavor - 1]);
Console.WriteLine("Container: {0}",
Container[ChoiceContainer - 1]);
Console.WriteLine("Ingredient: {0}",
Ingredient[ChoiceIngredient - 1]);
Console.WriteLine("Scoops: {0}", Scoops);
Console.WriteLine("Total Price: {0:C}", TotalPrice);
Console.WriteLine("=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=\n");
}
public void SaveOrder()
{
string strNameOfFile;
Console.Write("Please enter your initials or the name " +
"we will use to remember your order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
// Find out if the user entered a name of a file
// that is already in the machine
if (File.Exists(strNameOfFile))
{
char answer;
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Create);
BinaryWriter bnwIceCream =
new BinaryWriter(stmIceCream);
try
{
// If so, find out if the user wants to
// replace the old file
Console.WriteLine("The file you entered exists already.");
Console.Write("Do you want to replace it(y/n)?");
answer = char.Parse(Console.ReadLine());
// If the customer wants to replace it...
if (answer == 'y' || answer == 'Y')
{
// ... do so
Console.WriteLine("The former order with the same " +
"name will be replaced");
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}", strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
// If the customer wants to save the new order with
// a different name
else if (answer == 'n' || answer == 'N')
{
// Ask the user to enter a name to remember the order
Console.Write("Please enter a name we will use " +
"to remember this order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
stmIceCream =
new FileStream(strNameOfFile, FileMode.Create);
bnwIceCream = new BinaryWriter(stmIceCream);
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}", strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
else
Console.WriteLine("Invalid Answer - We will close");
}
finally
{
bnwIceCream.Close();
stmIceCream.Close();
}
}
else
{
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Create);
BinaryWriter bnwIceCream =
new BinaryWriter(stmIceCream);
try
{
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}", strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
finally
{
bnwIceCream.Close();
stmIceCream.Close();
}
}
}
public void OpenOrder()
{
string strNameOfFile;
string SelectedFlavor;
string SelectedContainer;
string SelectedIngredient;
// Ask the user to enter a name of a previously saved order
Console.Write("Please enter the name you previously " +
"gave to remember your order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Open);
BinaryReader bnrIceCream =
new BinaryReader(stmIceCream);
try
{
// Find out if this order was previously saved in the machine
if (File.Exists(strNameOfFile))
{
// If so, open it
SelectedFlavor = bnrIceCream.ReadString();
SelectedContainer = bnrIceCream.ReadString();
SelectedIngredient = bnrIceCream.ReadString();
Scoops = bnrIceCream.ReadInt32();
TotalPrice = bnrIceCream.ReadDecimal();
// And display it to the user
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Previous Order: {0}", strNameOfFile);
Console.WriteLine("Flavor: {0}", SelectedFlavor);
Console.WriteLine("Container: {0}", SelectedContainer);
Console.WriteLine("Ingredient: {0}", SelectedIngredient);
Console.WriteLine("Scoops: {0}", Scoops);
Console.WriteLine("Total Price: {0:C}\n", TotalPrice);
}
else
Console.WriteLine("The name you entered is not " +
"registered in our previous orders");
}
finally
{
bnrIceCream.Close();
stmIceCream.Close();
}
}
}
}
|
Accédez au fichier Program.cs et changez le comme suit :
using System;
namespace IceCream4
{
class Program
{
static int Main(string[] args)
{
char answer = 'n';
IceCream ic = new IceCream();
Request process = new Request(ic.ProcessAnOrder);
Console.Write("Do you want to re-order a previously " +
"saved order(y/n)? ");
answer = char.Parse(Console.ReadLine());
if (answer == 'y' || answer == 'Y')
ic.OpenOrder();
else
{
process();
Console.Write("Do you want us to remember this " +
"order the next time you come to " +
"get your ice scream (y/n)? ");
answer = char.Parse(Console.ReadLine());
if (answer == 'y' || answer == 'Y')
ic.SaveOrder();
else
Console.WriteLine("\nIt was nice serving you." +
"\nCome Again!!!\n");
}
return 0;
}
}
}
|
- Exécutez l'application et l'examiner. Voici un exemple :
Do you want to re-order a previously saved order(y/n)? n
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
Ice Scream Vending Machine
-----------------------------------
What type of flavor do you want?
1 - Vanilla
2 - Cream of Cocoa
3 - Chocolate Chip
4 - Organic Strawberry
5 - Butter Pecan
6 - Cherry Coke
7 - Chocolate Brownies
8 - Caramel Au Lait
9 - Chunky Butter
10 - Chocolate Cookie
Your Choice? 6
-----------------------------------
What type of container do you want?
1 - Cone
2 - Cup
3 - Bowl
Your Choice? 2
-----------------------------------
Do you want an ingredient or not
1 - No Ingredient
2 - Peanuts
3 - M & M
4 - Cookies
Your Choice? 1
-----------------------------------
How many scoops(1, 2, or 3)? 2
-----------------------------------
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
Ice Scream Order
-----------------------------------
Flavor: Cherry Coke
Container: Cup
Ingredient: No Ingredient
Scoops: 2
Total Price: $2.60
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
Do you want us to remember this order the next time you
come to get your ice scream (y/n)? n
It was nice serving you.
Come Again!!!
Press any key to continue . . .
|
- Fermez la fenêtre DOS
- Exécutez l'application et l'examiner. Écrire un nom de fichier
faux. Voici un exemple :
Do you want to re-order a previously saved order(y/n)? y
Please enter the name you previously gave to remember your order: dtr
Unhandled Exception: System.IO.FileNotFoundException: Could not find file 'C:\Do
cuments and Settings\Administrator\My Documents\Visual Studio 2005\Projects\Vend
ingMachine4\IceCream4\bin\Release\dtr.icr'.
File name: 'C:\Documents and Settings\Administrator\My Documents\Visual Studio 2
005\Projects\VendingMachine4\IceCream4\bin\Release\dtr.icr'
at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, I
nt32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions o
ptions, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy)
at System.IO.FileStream..ctor(String path, FileMode mode)
at IceCream4.IceCream.OpenOrder() in C:\Documents and Settings\Administrator
\My Documents\Visual Studio 2005\Projects\VendingMachine4\IceCream4\IceCream.cs
:line 360
at IceCream4.Program.Main(String[] args) in C:\Documents and Settings\Adminis
trator\My Documents\Visual Studio 2005\Projects\VendingMachine4\IceCream4\Progra
m.cs:line 18
Press any key to continue . . .
|
- Fermez la fenêtre DOS
|
Manipulation d'exception du .NET
Framework pour le traitement de fichier
|
|
Dans la leçon précédente comme dans notre
introduction au traitement de fichier, nous nous sommes comportés comme
si tout était bien. Malheureusement, le traitement de fichier peut être
très strict dans ses tâches. Basé sur ceci, .NET Framework fournit diverses classes
d'Exceptions orientées pour traiter avec presque
n'importe quel type d'exception à laquelle vous pouvez penser.
Un des aspects les plus importants du traitement de
fichier est le nom du fichier qui sera traité. Dans certains cas
vous pouvez fournir ce nom à l'application ou au document. Dans
quelques autres cas, vous laisseriez l'utilisateur indiquer le nom du
chemin. Indépendamment de la façon dont le nom du dossier serait
fourni au logiciel d'exploitation, quand ce nom agi dessus, le
compilateur est invité à travailler sur le fichier. Si le fichier n'existe pas, l'opération ne peut pas être
exécutée. En outre, le
compilateur rejetterait une erreur. Il y a beaucoup d'autres exceptions
qui peuvent être rejetées en raison de quelque chose de mauvais
survenue pendant
le traitement de fichier :
FileNotFoundException : L'exception jetée
quand un fichier n'a pas été trouvé est de type FileNotFoundException.
Voici un exemple de manipulation :
using System;
using System.IO;
public class Program
{
static int Main(string[] args)
{
/* string NameOfFile = "Members.clb";
FileStream fstPersons =
new FileStream(NameOfFile, FileMode.Create);
BinaryWriter wrtPersons = new BinaryWriter(fstPersons);
try
{
wrtPersons.Write("James Bloch");
wrtPersons.Write("Catherina Wallace");
wrtPersons.Write("Bruce Lamont");
wrtPersons.Write("Douglas Truth");
}
finally
{
wrtPersons.Close();
fstPersons.Close();
}*/
string NameOfFile = "Members.clc";
string strLine = null;
try
{
FileStream fstMembers =
new FileStream(NameOfFile, FileMode.Open);
BinaryReader rdrMembers = new BinaryReader(fstMembers);
try
{
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
strLine = rdrMembers.ReadString();
Console.WriteLine(strLine);
}
finally
{
rdrMembers.Close();
fstMembers.Close();
}
}
catch (FileNotFoundException ex)
{
Console.Write("Error: " + ex.Message);
Console.WriteLine(" May be the file doesn't exist " +
"or you typed it wrong!");
}
return 0;
}
}
Voici un exemple de ce que ceci produirait :
Error: Could not find file 'C:\Documents and Settings\Administrator\Local
Settings\Application Data\Temporary
Projects\ConsoleApplication1\bin\Release\Members.clc'.
May be the file doesn't exist or you typed it wrong!
Press any key to continue . . .
IOException : Comme mentionné déjà,
pendant le traitement de fichier, n'importe quoi a pu tourner mal. Si
vous ne savez pas ce qui a causé une erreur, vous pouvez rejeter
l'exception IOException.
|
Étude
pratique : Manipulation des exceptions de traitement de fichier
|
|
- Pour ejeter des exceptions, changez les méthodes de traitement de
fichier à partir du fichier IceScream.cs comme suit :
using System;
using System.IO;
namespace IceCream4
{
delegate void Request();
// This class is used to create and manage an ice scream
// and to process an order
public sealed class IceCream
{
// This is the base price of an ice scream
// Optional values may be added to it
public const decimal BasePrice = 1.55M;
// These arrays are used to build the components
// of various ice screams
// In C#, we can allocate an array's memory in
// the body of the class
private string[] Flavor;
private string[] Container;
private string[] Ingredient;
// Additional factor used to process an ice scream order
private int Scoops;
private decimal TotalPrice;
// Variables that will hold the user's choice
// These are declared "globally" so they can be
// shared among methods
int ChoiceFlavor;
int ChoiceContainer;
int ChoiceIngredient;
// This default constructor is the best place for
// us to initialize the array
public IceCream()
{
Flavor = new string[10];
Flavor[0] = "Vanilla";
Flavor[1] = "Cream of Cocoa";
Flavor[2] = "Chocolate Chip";
Flavor[3] = "Organic Strawberry";
Flavor[4] = "Butter Pecan";
Flavor[5] = "Cherry Coke";
Flavor[6] = "Chocolate Brownies";
Flavor[7] = "Caramel Au Lait";
Flavor[8] = "Chunky Butter";
Flavor[9] = "Chocolate Cookie";
Ingredient = new string[4];
Ingredient[0] = "No Ingredient";
Ingredient[1] = "Peanuts";
Ingredient[2] = "M & M";
Ingredient[3] = "Cookies";
Container = new string[3];
Container[0] = "Cone";
Container[1] = "Cup";
Container[2] = "Bowl";
}
// This method requests a flavor from the user and
// returns the choice
public void ChooseFlavor()
{
// Make sure the user selects a valid number
//that represents a flavor...
do
{
// In case the user types a symbol that
// is not a number
try
{
Console.WriteLine("What type of flavor do you want?");
for (int i = 0; i < Flavor.Length; i++)
Console.WriteLine("{0} - {1}", i + 1, Flavor[i]);
Console.Write("Your Choice? ");
ChoiceFlavor = int.Parse(Console.ReadLine());
}
catch (FormatException) // display an appropriate message
{
Console.WriteLine("You must enter a valid number " +
"and no other character!");
}
// If the user typed an invalid number out of the
// allowed range
// let him or her know and provide another chance
if (ChoiceFlavor < 1 || ChoiceFlavor > Flavor.Length)
Console.WriteLine("Invalid Choice - Try Again!\n");
} while (ChoiceFlavor < 1 || ChoiceFlavor > Flavor.Length);
}
// This method allows the user to select a container
public void ChooseContainer()
{
// Make sure the user selects a valid number that
// represents a container
do
{
// If the user types a symbol that is not a number
try
{
Console.WriteLine("What type of container do you want?");
for (int i = 0; i < Container.Length; i++)
Console.WriteLine("{0} - {1}", i + 1, Container[i]);
Console.Write("Your Choice? ");
ChoiceContainer = int.Parse(Console.ReadLine());
}
catch (FormatException) // display an appropriate message
{
Console.WriteLine("You must enter a valid " +
"number and no other character!");
}
// If the user typed an invalid number out of the
// allowed range
// let him or her know and provide another chance
if ((ChoiceContainer < 1) ||
(ChoiceContainer > Container.Length))
Console.WriteLine("Invalid Choice - Try Again!");
} while ((ChoiceContainer < 1) ||
(ChoiceContainer > Container.Length));
}
public void ChooseIngredient()
{
do
{
try
{
Console.WriteLine("Do you want an ingredient or not");
for (int i = 0; i < Ingredient.Length; i++)
Console.WriteLine("{0} - {1}",
i + 1,
Ingredient[i]);
Console.Write("Your Choice? ");
ChoiceIngredient = int.Parse(Console.ReadLine());
}
catch (FormatException)
{
Console.WriteLine("You must enter a valid " +
"number and no other character!");
}
if ((ChoiceIngredient < 1) ||
(ChoiceIngredient > Ingredient.Length))
Console.WriteLine("Invalid Choice - Try Again!");
} while ((ChoiceIngredient < 1) ||
(ChoiceIngredient > Ingredient.Length));
}
public void SpecifyNumberOfScoops()
{
do
{
try
{
Console.Write("How many scoops(1, 2, or 3)? ");
Scoops = int.Parse(Console.ReadLine());
}
catch (FormatException)
{
Console.WriteLine("You must enter a valid number " +
"and no other character!");
}
if (Scoops < 1 || Scoops > 3)
Console.WriteLine("Invalid Choice - Try Again!");
} while (Scoops < 1 || Scoops > 3);
}
// This method is used to process a customer order
// It uses the values of the above methods
public void ProcessAnOrder()
{
// int ChoiceFlavor;
// int ChoiceContainer;
// int ChoiceIngredient;
decimal PriceIngredient, PriceScoop;
// Let the user know that this is a vending machine
Console.WriteLine("=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=");
Console.WriteLine("Ice Scream Vending Machine");
Console.WriteLine("-----------------------------------");
// Let the user select the components of the ice scream
Request Get = new Request(ChooseFlavor);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(ChooseContainer);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(ChooseIngredient);
Get();
Console.WriteLine("-----------------------------------");
Get = new Request(SpecifyNumberOfScoops);
Get();
Console.WriteLine("-----------------------------------");
// If the user selects an ingredient instead of "No Ingredient",
// add $0.50 to the order
if ((ChoiceIngredient == 2) ||
(ChoiceIngredient == 3) ||
(ChoiceIngredient == 4))
PriceIngredient = 0.50M;
else
PriceIngredient = 0.00M;
// Instead of multiplying a number scoops to a value,
// We will use an incremental value depending on
// the number of scoops
if (Scoops == 1)
PriceScoop = 0.65M;
else if (Scoops == 2)
PriceScoop = 1.05M;
else
PriceScoop = 1.55M;
// Calculate the total price of the ice scream
TotalPrice = BasePrice + PriceScoop + PriceIngredient;
// Create the ice scream...
// And display a receipt to the user
DisplayReceipt();
}
// This method is used to display a receipt to the user
public void DisplayReceipt()
{
Console.WriteLine("\n=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=");
Console.WriteLine("Ice Scream Order");
Console.WriteLine("-----------------------------------");
Console.WriteLine("Flavor: {0}",
Flavor[ChoiceFlavor - 1]);
Console.WriteLine("Container: {0}",
Container[ChoiceContainer - 1]);
Console.WriteLine("Ingredient: {0}",
Ingredient[ChoiceIngredient - 1]);
Console.WriteLine("Scoops: {0}", Scoops);
Console.WriteLine("Total Price: {0:C}", TotalPrice);
Console.WriteLine("=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=\n");
}
public void SaveOrder()
{
string strNameOfFile;
Console.Write("Please enter your initials or the name " +
"we will use to remember your order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
try
{
// Find out if the user entered a name of a file
// that is already in the machine
if (File.Exists(strNameOfFile))
{
char answer;
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Create);
BinaryWriter bnwIceCream =
new BinaryWriter(stmIceCream);
try
{
// If so, find out if the user wants to
// replace the old file
Console.WriteLine("The file you entered exists already.");
Console.Write("Do you want to replace it(y/n)?");
answer = char.Parse(Console.ReadLine());
// If the customer wants to replace it...
if (answer == 'y' || answer == 'Y')
{
// ... do so
Console.WriteLine("The former order with the same " +
"name will be replaced");
Console.WriteLine("\n=-= Ice Scream " +
"Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}", strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
// If the customer wants to save the new order with
// a different name
else if (answer == 'n' || answer == 'N')
{
// Ask the user to enter a name to remember the order
Console.Write("Please enter a name we will use " +
"to remember this order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
try
{
stmIceCream = new FileStream(strNameOfFile,
FileMode.Create);
bnwIceCream = new BinaryWriter(stmIceCream);
Console.WriteLine("\n=-= Ice Scream " +
"Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}",
strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
catch (IOException)
{
Console.Write("\nThe file you wanted us to " +
"create exists already. ");
Console.WriteLine("In case it was registered " +
"by a different customer, " +
"we will not delete it.");
}
}
else
Console.WriteLine("Invalid Answer - We will close");
}
catch (IOException)
{
Console.Write("\nThat file exists already. ");
Console.WriteLine("We need to preserve it just in " +
"case another customer will require it.");
}
finally
{
bnwIceCream.Close();
stmIceCream.Close();
}
}
else
{
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Create);
BinaryWriter bnwIceCream =
new BinaryWriter(stmIceCream);
try
{
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Saving Order: {0}", strNameOfFile);
bnwIceCream.Write(Flavor[ChoiceFlavor - 1]);
bnwIceCream.Write(Container[ChoiceContainer - 1]);
bnwIceCream.Write(Ingredient[ChoiceIngredient - 1]);
bnwIceCream.Write(Scoops);
bnwIceCream.Write(TotalPrice);
}
finally
{
bnwIceCream.Close();
stmIceCream.Close();
}
}
}
catch (IOException ex)
{
Console.WriteLine("\nError: " + ex.Message);
Console.WriteLine("Operation Canceled: The file you want " +
"to create exists already.");
}
}
public void OpenOrder()
{
string strNameOfFile;
string SelectedFlavor;
string SelectedContainer;
string SelectedIngredient;
// Ask the user to enter a name of a previously saved order
Console.Write("Please enter the name you previously " +
"gave to remember your order: ");
strNameOfFile = Console.ReadLine();
strNameOfFile = strNameOfFile + ".icr";
try
{
FileStream stmIceCream =
new FileStream(strNameOfFile, FileMode.Open);
BinaryReader bnrIceCream =
new BinaryReader(stmIceCream);
try
{
// Find out if this order was previously saved in the machine
if (File.Exists(strNameOfFile))
{
// If so, open it
SelectedFlavor = bnrIceCream.ReadString();
SelectedContainer = bnrIceCream.ReadString();
SelectedIngredient = bnrIceCream.ReadString();
Scoops = bnrIceCream.ReadInt32();
TotalPrice = bnrIceCream.ReadDecimal();
// And display it to the user
Console.WriteLine("\n=-= Ice Scream Vending Machine =-=");
Console.WriteLine(" Previous Order: {0}", strNameOfFile);
Console.WriteLine("Flavor: {0}", SelectedFlavor);
Console.WriteLine("Container: {0}", SelectedContainer);
Console.WriteLine("Ingredient: {0}", SelectedIngredient);
Console.WriteLine("Scoops: {0}", Scoops);
Console.WriteLine("Total Price: {0:C}\n", TotalPrice);
}
else
Console.WriteLine("The name you entered is not " +
"registered in our previous orders");
}
finally
{
bnrIceCream.Close();
stmIceCream.Close();
}
}
catch (FileNotFoundException ex)
{
Console.Write("\nError: " + ex.Message);
Console.WriteLine("It is unlikely that the file exists in " +
"our machine's register.");
}
}
}
}
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