I've recently written this short application in C#:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Checker
{
class Program
{
static void Main(string[] args)
{
Properties.Settings.Default.Save();
Program re = new Program();
re.next();
}
public void next()
{
Console.WriteLine("Have you already entered name?");
int ch = int.Parse(Console.ReadLine());
if (ch == 0)
{
Console.WriteLine("What is your name?");
String name = Console.ReadLine();
Console.WriteLine("Thank you!");
Console.ReadKey();
}
Console.WriteLine("Your name is " + name);
}
}
}
Now, I've created a settings file, and created a "name" variable there, with the "String" type.
The scope of it is "User".
So I want it to load the "name" variable with the properties line, but I can't even compile the program because of this error:
Error 1 The name 'name' does not exist in the current context
How can I solve it?
The answer to your problem becomes a little more apparent when you indent:
String name;
if (ch == 0)
{
Console.WriteLine("What is your name?");
name = Console.ReadLine();
Console.WriteLine("Thank you!");
Console.ReadKey();
}
else
{
name = Settings.Default.name;
}
Console.WriteLine("Your name is " + name);
Now you can see that you defined a String called name inside the if-block, thus using it in the Console.WriteLine outside the if-block is out of scope! Move that last Console.WriteLine inside the if-block to solve the scoping issue.
Edit: Based on your comment, your code needs a bit more logic to attain what you're trying to do. I updated my snippet above to accomplish what I think you're trying to do.
You declared that variable inside the if block.
As the compiler is trying to tell you, it doesn't exist outside that block.
If you want to use your Settings class, write Settings.Default.Name.
Your intentions are a bit unclear, but to me it seems as though you are trying to have the application display the name of the user if it has already been saved or ask for it if it hasn't. If that is the case, something like this should work:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Checker
{
class Program
{
static void Main(string[] args)
{
Program re = new Program();
re.next();
Properties.Settings.Default.Save();
}
public void next()
{
String name = Settings.Default.name;
if (String.IsNullOrEmpty(name))
{
Console.WriteLine("What is your name?");
name = Console.ReadLine();
Settings.Default.name = name;
Console.WriteLine("Thank you!");
Console.ReadKey();
}
else
{
Console.WriteLine("Your name is " + name);
}
}
}
}
In your OP, your settings were not being saved before the program exited nor were you setting the name property.
Related
I have coded a system based of the theory that while loops can work anywhere in a system. So once a while loop has been passed by it can run. Here is a simple version of my code:
using System;
namespace test___login
{
class Program
{
static void Main(string[] args)
{
string location = "homepage";
while (location.Equals("Homepage", StringComparison.InvariantCultureIgnoreCase))
{
Console.WriteLine("homepage");
Console.WriteLine("WHere to now: ");
location = Console.ReadLine();
}
while (location.Equals("login", StringComparison.InvariantCultureIgnoreCase))
{
Console.WriteLine("login");
Console.WriteLine("Where to now: ");
location = Console.ReadLine();
}
}
}
}
So I assumed that once the variable changes from "login" to "homepage" in the second while loop, would mean the first while loop would run once again. Is my theory on how the code works wrong or am i simply not typing the right thing. I just started last week so sorry for the basic question
It wouldn't run again, because the code has already executed past that line so unless you call it again, the next thing down the line will execute, in your case nothing - this is called procedural programming.
Why don't you make one while loop, and a switch statement instead.
bool run = true;
while (run)
{
Console.WriteLine("WHere to now: ");
string location = Console.ReadLine();
switch(location.ToLower()){
case "homepage":
Console.WriteLine("HomePage");
break;
default:
run = false;
break;
}
}
Not with the way you have your code currently structured. It will exit the application. You need to surround all of that with one more while loop, which can be similar to your other loops. See below:
using System;
namespace test___login {
class Program
{
static void Main(string[] args)
{
string location = "homepage";
while (!location.ToUpper().Equals("EXIT"))
{
while (location.Equals("Homepage", StringComparison.InvariantCultureIgnoreCase))
{
Console.WriteLine("homepage");
Console.WriteLine("WHere to now: ");
location = Console.ReadLine();
}
while (location.Equals("login", StringComparison.InvariantCultureIgnoreCase))
{
Console.WriteLine("login");
Console.WriteLine("Where to now: ");
location = Console.ReadLine();
}
}
}
}
}
Why when I type "gamble" the first time, only the if statement works? It's no use typing anything else, it still adds 10 woods. And why when I type anything else the first time, just the else statement works? It is no use typing "gamble, will continue saying " Write '' gamble '' to hit the tree. " PS: The variable its int = woods; and string gamble;
Console.WriteLine("You have {0} woods", woods);
Console.WriteLine("Write ''gamble'' to hit the tree");
gamble = Console.ReadLine();
bool loop = true;
while (loop)
{
if (gamble.Contains("gamble"))
{
woods = woods + 10;
Console.Clear();
}
else
{
Console.WriteLine("Write ''gamble'' to hit the tree");
}
Console.WriteLine("You have {0} woods", woods);
Console.ReadLine();
}
gamble = Console.ReadLine();
You only set gamble in the beginning. In the loop it is never changed. So it keeps using the first value over and over again.
Add gamble = to the last line of the loop.
If I understand what your are describing, you forgot to read into gamble again
Console.WriteLine("You have {0} woods", woods);
gamble = Console.ReadLine();
}
At the end of the while loop, you are doing Console.ReadLine() but not storing it. You need gamble = Console.ReadLine() to store the scanned string in the "gamble" variable.
Because loop is always true. You should change it to false after if and else statements...
The reason it's adding 10 wood regardless if there is something else than "gamble" in the console line, is because you're writing "gamble" in the returning message.
else {Console.WriteLine("Write ''gamble'' to hit the tree");} is the problem here.
You can fix it by either not writing the word "gamble" inside the returning message, or find a clever way to not have it run in a while(true) loop.
You can, for example, use the main method to have it run the function you're going to run just once.
Something like this.
using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace ConsoleApp1
{
class Program
{
// Set a `wood` variable for the class.
protected int wood { get; set; }
static void Main(string[] args)
{
Program program = new Program(); // Making use of non-static methods.
program.Handler();
}
public void Handler()
{
Console.WriteLine("Write \"gamble\" to hit the tree.");
string message = Console.ReadLine();
if (message == "gamble")
{
addWood(); // Call the non-static method.
}
}
public bool addWood()
{
this.wood = this.wood + 10;
Console.WriteLine("You now have {0} wood!", this.wood);
Handler(); // Call the Handler() method again for infinite loop.
return true;
}
}
}
WARNING: The program will exit if there is something else than "gamble" written.
Edit- Based on Steve and Marco's replies I've edited the code. In the lessons the professor has used StreamWriter so I believe he probably wants us to the same. Here is the revised code:
using System;
using System.IO;
namespace Assignment4
{
class Program
{
static void Main(string[] args)
{
FavoriteNumber();
}
static void FavoriteNumber()
{
Console.WriteLine("Please input your favorite number: ");
var result = Console.ReadLine();
using (StreamWriter writer = new StreamWriter("FavoriteNumber.txt"))
{
writer.WriteLine(result);
}
}
}
}
I am taking a Computer Programming Fundamentals class as a GenEd requirement for an unrelated degree, meaning I am very much a novice at this and really was just interested in gaining a very basic understanding of how it all works. That being said, this is probably a very simple question for most users on this forum. The instructions for this assignment are as follows:
"Write a C# program which uses a custom method to accept user input and save the input to a text file."
Can someone please tell me if the code I wrote meets these parameters? I was really lost with this assignment but am hoping that by some miracle I got it right. Thank you in advance for your help!
using System;
using System.IO;
namespace Assignment4
{
class Program
{
static void Main(string[] args)
{
}
static void addNumbers(int x, int y)
{
int result = x+y;
using (StreamWriter writer = new StreamWriter("Assignment4.txt"))
{
writer.WriteLine(result);
}
}
}
}
You need to accept user input somewhere. You can do that with Console.ReadLine(). It waits until the user types in something and then continues.
Also, you do not need a StreamWriter for this. You can just use File.WriteAllText()
The result would look something like this:
static void WriteTextToFile()
{
WriteTextToFile();
}
static void WriteTextToFile()
{
Console.WriteLine("Please enter some value:");
var valueToWrite = Console.ReadLine();
File.WriteAllText("Assignment4.txt", valueToWrite);
Console.WriteLine("Thanks alot. Press a key to close.");
Console.ReadKey();
}
I am currently studying C# and am trying to prepare for next weeks lessons which will be the introduction of classes and methods. To that end i have attempted to build a class called MaxBox which is meant to be a general utility class that I can store some general functions in like 'Displaying a String' or 'Play Again'. I've built my main file (Program) and my class file (MaxBox) and lines #23, #28 and #59 return the same general error 'An object reference is required for the non-static field, method, or property 'program.MaxBox.DisplayStr(string)'. #57 returns a similar error 'An object reference is required for the non-static field, method, or property 'program.MaxBox.PlayAgain()'
I'm a total newb really, and i'm wrestling with objects, I've done some research to get myself this far but I don't understand the language enough yet to be able to understand what the resources I've read are saying I guess to solve this error. Help and guidance is greatly appreciated. I'm still in my first weeks and really I know nothing.
Program:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading; // needed for close
using System.Threading.Tasks;
namespace a020_Breakcase_MeaningOfNames_C
{
class Program
{
public void Play()
{
/*
* Conditionals - Use switch/Case statement too:
* Evaluate user data (name)
* Return meaning of name evaluated
* OR
* Return 'Name not found' error message
* Say goodbye
*/
MaxBox.DisplayStr("What's in a name? Let's find out!");
Console.Write("\n\n");
do
{
MaxBox.DisplayStr("Enter Name: ");
string uName = Console.ReadLine().ToLower();
switch (uName)
{
case "doyle":
Console.WriteLine("Doyle means descendant of Dubhghalle");
break;
case "fiona":
Console.WriteLine("Fiona is considered to be a Latinised form of the Gaelic word fionn, meaning \"white\", \"fair\".");
break;
case "hunter":
Console.WriteLine("Hunter means to search with purpose");
break;
case "liam":
Console.WriteLine("This name is a short form of the Irish name Uilliam (William) which is now use independently as a given name. As a Hebrew name, Liam means \"my people; I have a nation\".");
break;
case "max":
Console.WriteLine("Short for of Maximilian, Maxwell, and the various name using it as a first syllable.");
break;
case "portia":
Console.WriteLine("It is of Latin origin. Feminine form of a Roman clan name. Portia was used by Shakespeare as the name of a clever, determined young heroine in \"The Merchant of Venice\" who disguises herself as a lawyer to save her husband's life.");
break;
default:
Console.WriteLine("I'm sorry but I don't know the meaning of the name " + uName + ".");
break;
}
} while (MaxBox.PlayAgain());
MaxBox.DisplayStr("C#eers!");
}
static void Main(string[] args)
{
Program myProgram = new Program();
myProgram.Play();
Console.Read();
}
}
}
My Class:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace a020_Breakcase_MeaningOfNames_C
{
class MaxBox
{
/*
* MaxBox is my general functions class
* Contains
* DisplayStr() - Display the string given
* PlayAgain() - If True, runs program again
*/
public String uName;
public String command;
public void DisplayStr(String StrTxt)
{ Console.Write(StrTxt); }
public Boolean PlayAgain()
{
Console.Write("\n\nDo you want to play again? (y)es or (n)o: ");
String command = Console.ReadLine().ToLower().Trim();
if (command == "y" || command == "yes") return true;
return false;
}
}
}
MaxBox's methods are not static, you need an instance of it.
MaxBox maxBox = new MaxBox();
at the beginning of your main class. Then
maxBox.DisplayStr(....)
also, just to get you thinking, you can replace:
if (command == "y" || command == "yes") return true;
return false;
with
return (command == "y" || command == "yes");
The methods PlayAgain and DisplayStr are instance methods on the type MaxBox. In order to call them you need an instance of MaxBox on which to call them. Right now you are trying to call them via the type name which only works for static methods
MaxBox.DisplayStr("hello world"); // wrong
MaxBox mb = new MaxBox();
mb.DisplayStr("hello world"); // right
It is possible to define methods such that you can invoke them from the type name. But doing so requires that they be marked as static
class MaxBox {
public static void DisplayStr2(string str){ ... }
}
MaxBox.DisplayStr2("hello world"); // right
I'm a newbie in java from c# background. In c# when i want to make sure the user cannot does null data in the Console Application i make a loop like
static void Main(string[] args)
{
Console.WriteLine("Enter your name : ");
string name = Console.ReadLine();
while (name == "")
{
Console.WriteLine("Enter your name : ");
name = Console.ReadLine();
}
}
Now I want to implement the same in java. I am using
public static void main(String[] args) {
// TODO code application logic here
System.out.println("Enter your name : ");
String pname;
Scanner scan=new Scanner(System.in);
pname=scan.next();
while ("".equals(pname))
{
System.out.println("Enter your name : ");
pname=scan.next();
}
}
But when a null value is entered, the output doesn't show the Enter your name again it only moves one line waiting for a value to be entered.
What am i doing wrong?
Try using nextLine() instead. next() only gets up to the next space, nextLine() gets the next linebreak. I vaguely remember this from my java class in college.
while ("".equals(pname))
{
System.out.println("Enter your name : ");
pname=scan.next();
}
Instead use
while (pname.equals(""))
{
System.out.println("Enter your name : ");
pname=scan.next();
}
If you look at javadocs for equals, you will know what i am talking about.
And also a hint, i started using buffred reader when i started coding in java
You can use:
while (pname == null || "".equals(pname))
{
System.out.println("Enter your name : ");
pname = scanner.nextLine();
}
I also faced similar type of problem once. The problem is not in while loop. It is in reusing same Scanner object. Try creating new Scanner object each time.
public static void main(String[] args) {
// TODO code application logic here
System.out.println("Enter your name : ");
String pname;
Scanner scan=new Scanner(System.in);
pname=scan.next();
while (pname.equals(""))
{
System.out.println("Enter your name : ");
scan = new Scanner(System.in);
pname=scan.next();
}
}