I am currently Trying to learn C#, I am coming from another Language so learning C# has been a breeze (so far). However, I was creating a console application in which the user enters a username and password then they get logged in. When they are logged in, I simply ask them for what they want and they type in their request. Now the thing is, whenever they pass the if/else if/else statements, I move them to a new method that greets them with a "Hello, welcome, Please enter a request". after they put in the request, I want the console to only say "Please enter a request". Thus I want to check if the method is being ran for the first time. Any ideas on how to do it.
I think this should do it
using System;
namespace ConsoleApplication1
{
class Program
{
static bool hasRun = false;
static void Main(string[] args)
{
GreetUser();// first call
GreetUser();// second call
}
private static void GreetUser()
{
var message = "Hello, welcome. Please enter a request: ";
// could be refactored to
if (hasRun)
{
message = "Please enter a request: ";
}
Console.WriteLine(message);
var requestText = Console.ReadLine();
hasRun = true;
}
}
}
first call to GreetUser() will be:
Hello, welcome. Please enter a request:
second and subsequent calls to GreetUser() will be:
Please enter a request:
EDIT:
Oh one thing I forgot is that you could further refactor the message using ternary operator to this:
private static void GreetUser()
{
var message = (!hasRun ? "Hello, welcome. " : string.Empty) + "Please enter a request: ";
Console.WriteLine(message);
var requestText = Console.ReadLine();
hasRun = true;
}
Turns 4 lines of code into 1
Related
This question already has answers here:
Use a variable from another method in C#
(2 answers)
Closed 1 year ago.
Hey I'm very very new to c# coding and OOP, I'm currently working on a system that allows users to create login details, and then login with said details, however when I get to the part where I verify the users details I am having issues getting it to recognize my object, AccName, credentialCheck() can't successfully get the information from accountCreation(), I know this is a very basic thing to know but I have tried so many things and none of them have worked, or I haven't been doing them properly. My code is shown below and any guidance that could be provided would be greatly appreciated.
static void accountCreation()
{
Console.Write("Username: ");
string userNameInput = Console.ReadLine();
Console.Write("Email: ");
string userEmailInput = Console.ReadLine();
Console.Write("Password: ");
string userPasswordInput = Console.ReadLine();
Account AccName = new Account($"{userNameInput}", $"{userEmailInput}", $"{userPasswordInput}");
Console.Write($"{userNameInput} Registered successfully");
Console.WriteLine();
}
static void credentialCheck()
{
Console.Write("Email: ");
string userEmailCheck = Console.ReadLine();
Console.Write("Password: ");
string userPasswordCheck = Console.ReadLine();
if (userEmailCheck == AccName.userEmail )
{
Console.WriteLine();
Console.WriteLine("Success");
}
I suppose you are calling credentialCheck() just after accountCreation() and in the same thread. That out of the way, I supposed you have accName as a static variable and your class overall looks like this:
class Login {
protected static Account accName;
static void accountCreation()
{
// ...
accName = new Account(userNameInput, userEmailInput, userPasswordInput);
}
}
This means the variable accName remains as far as the execution context is concerned and not immediately destroyed after accountCreation() returns.
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.
Keep getting the error message does not contain a static main method for suitable entry point. Would anyone be able to explain this error to me and possibly help me fix it? Thanks. New to C#
{
class Authenticator
{
private Dictionary<string, string> dictionary = new Dictionary<string, string>();
public void IntialValues()
{
dictionary.Add("username1", "password1");
dictionary.Add("username2", "password2");
dictionary.Add("username3", "password3");
dictionary.Add("username4", "password4");
dictionary.Add("username5", "password5");
}
public bool Authenticate(Boolean authenticated)
{
Console.WriteLine("Please enter a username");
string inputUsername = Console.ReadLine();
Console.WriteLine("Please enter your password");
string inputPassword = Console.ReadLine();
if (dictionary.ContainsKey(inputUsername) && dictionary[inputUsername] == inputPassword)
{
authenticated = true;
}
else
{
authenticated = false;
}
return authenticated;
}
}
}
If all of your code consists only of the block shown above then the error is more than clear. A Main method is required in your program.
The Main method is, by convention, the default point where the code starts executing. You can get here a more in depth explanation
So, for example, you need to add the following code
class Authenticator
{
static void Main(string[] args)
{
Authenticator au = new Authenticator();
au.InitialValues();
if(au.Authenticate())
Console.WriteLine("Authenticated");
else
Console.WriteLine("NOT Authenticated");
Console.WriteLine("Press Enter to end");
Console.ReadLine();
}
// Move the boolen variable inside the method
public bool Authenticate()
{
bool authenticated = false;
Console.WriteLine("Please enter a username");
string inputUsername = Console.ReadLine();
Console.WriteLine("Please enter your password");
string inputPassword = Console.ReadLine();
if (dictionary.ContainsKey(inputUsername) && dictionary[inputUsername] == inputPassword)
{
authenticated = true;
}
else
{
authenticated = false;
}
return authenticated;
}
}
By the way, you should remove the parameter passed in input to the Authenticate method. You should declare it as an internal variable, set it depending on the outcome of the check and return it.
However, you could remove that variable altogether writing
....
return (dictionary.ContainsKey(inputUsername)) &&
(dictionary[inputUsername] == inputPassword)
}
All executable programs must have a Main function somewhere in the project that is compiled to the exe.
If you just want to compile a class (eg to a dll) then you have to set that as the "project type" in visual studio.
The easiest way is to create a new project, but select class library as project type, and then paste your code in there. Alternatively you can use the command line to compile a file to a dll like so:
c:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe /target:library Authenticator.cs
so I'm writing a program that takes in a text line by line and then is supposed to output yes or no if the line contains the word problem.
The program is working, but I have to press enter twice to get the output.
The first enter I get, which is for the last line. And the second enter is so the while loop can break out.
Any suggestions to how I can improve this and not need the second enter?
using System;
using System.Collections.Generic;
namespace Tester
{
internal class Program
{
private static void Main(string[] args)
{
List<string> stringList = new List<string>();
string input = "";
while ((input = Console.ReadLine()) != string.Empty)
{
var s = input.ToLower();
stringList.Add(s.Contains("problem") ? "yes" : "no");
}
foreach (var str in stringList)
Console.WriteLine(str);
Console.ReadKey();
}
}
}
Well, for the last output you will type something. That's when (input = Console.ReadLine()) != string.Empty kicks in and the condition will pass.
The loop will come back to this line and block until you give it new input. Then supposedly you just type enter and in that case the loop will just exist. This is expected behaviour.
I'm not sure what upsets you about this. If you reaaaally wanted to get rid of the second enter, maybe you can put some token in your line (line /q or whatever) and whenever that is found in your line you know that you should break out of the loop.
Alternatively you can count how many inputs you get and make sure you get exactly 10 or 20 or whatever. When that number is reached, the loop will exit after the last input is processed.
Welcome to SO. :)
You can safely get rid of the last ReadKey. Given that you're creating a console application, you would normally rut it... in a console - as such, consoles don't close themselves after a program is done running. It's different if you run a console application in Windows OUTSIDE of a console - in this case, Windows will open a temporary console, run the app, and then close the console.
Also, if you're using Visual Studio, you can make VS wait for you by using the "start without debug" option (Ctrl+F5). VS will then add a "press enter to close" on it's own, at the end, to prevent the window from closing too fast, allowing you to check your outputs / exceptions.
One simple solution could be to output the "yes" or "no" values per line, rather than all at once at the end of your app.
Another way (which would require a bit more coding) would be to read individual keys, rather than lines - then you could react to the user pressing Esc, for example, rather than relying on an empty string ("extra" enter press).
You can use string.IsNullOrEmpty() and ToUpper() method is in general more accurate than ToLower(). So i'd probably refactor your code to something like :
private static void Main(string[] args)
{
List<string> stringList = new List<string>();
string input = "";
while(!string.IsNullOrEmpty(input = Console.ReadLine()))
stringList.Add(input.ToUpper().Contains("PROBLEM") ? "yes" : "no");
foreach (var str in stringList)
Console.WriteLine(str);
Console.ReadKey();
}
By the way welcome to SO... ;)
ok,do you mean this
static void Main(string[] args)
{
string input = "";
input = Console.ReadLine();
while (input != string.Empty)
{
if (input.Contains("problem"))
{
Console.WriteLine("yes");
}
else
{
Console.WriteLine("no");
}
input = Console.ReadLine();
}
Console.ReadKey();
}
maybe I know your intention.But if you want to break the while(input!=string.Empty) you must press an empty line.