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Problem with a while loop in C# - returns multiple

I am new to C# (1 week in) and I have been scratching my head with no answers. Simply put this is part of a text based game out of much larger file. The player has the option to accept or decline an incoming call. If y/Y or n/N is entered all is well. If I purposely enter an incorrect character the while loop will print "Please respond with 'Y' or 'N' only.." 3 times. I cannot work out why. If you enter 2 letters such as GG it will print it 4 times, 3 letters, 5 times and so on. I know this is an easy fix, I just need someone to point out what I've done wrong.
//INCOMING CALL
static void IncomingCall(char rawResponse)
{
// Convert response to upper
// (note method as ToUpper cannot be called conventionally on type char)
char response = char.ToUpper(rawResponse);
while (response != 'Y' && response != 'N')
{
WriteLine("Please respond with 'Y' or 'N' only..");
rawResponse = (char)Read();
response = char.ToUpper(rawResponse);
}
}
//called in main elsewhere in the file..
WriteLine("Incoming call from Tony. Press 'Y' to accept or 'N' to decline.");
char getInput = (char)Read();
IncomingCall(getInput);

I solved it, with your help by changing method to accept string and use ReadLine()
Changed
(response != 'Y' && response != 'N')
To
(response != "Y" && response != "N")
I did not realise '' and "" produce different results. I am used to Python. Thanks for the input guys.

I suggest changing the design. Let's implement ReadBool methods which incapsulates all the logic of bool value input:
public static bool ReadBool(string title) {
// We keep asking user until valid (N or Y) value is entered
while (true) {
// If we have a title, let's show it
if (!string.IsNullOrWhiteSpace(title))
Console.WriteLine(title);
// User has to press 'Y' or 'N'; no need for enter
var key = Console.ReadKey();
if (key.KeyChar == 'Y')
return true;
if (key.KeyChar == 'N')
return false;
// Invalid value; let user know it and try again
Console.WriteLine("Please respond with 'Y' or 'N' only..");
}
}
Possible usage:
bool acceptTony = ReadBool("Incoming call from Tony. Press 'Y' to accept or 'N' to decline.");
if (acceptTony) {
Console.WriteLine("Hi Tony!");
//TODO: put relevant code here
}
else {
Console.WriteLine("Declined");
//TODO: put relevant code here
}

Swap Read() with Console.Readline()[0];.
EDIT: Or change your method signature to be a string and leverage Console.Readline() as stated in the comments prior.

If statement multiple choice c#

string question1;
//Question 1
WriteLine("What is his favourite sport? ");
WriteLine("a) Soccer");
WriteLine("b) Basketball ");
WriteLine("c) Tennis ");
WriteLine("d) Football " );
Write("your answer is: ");
question1 = ReadLine();
if (question1 != "a" || question1 != "b" || question1 != "c")
Write("That is incorrect try again");
else
Write("that is correct");
No matter what letter I put it always gives me an incorrect try again, what am I doing wrong? Also would a while loop be better when trying to create a quiz game?

Those "or" (||) operators should almost certainly be "and" (&&) operators.
Think of what happens when you enter c, for example. Obviously, that will be c but it won't be a or b, so two of the sub-conditions will be true.
In fact, that's the case no matter which of a, b, or c that you enter (if you enter something else, all three will be true). And since an x || y || z is true if any of its sub-components is true, the expression as a whole is always true. The following table hopefully illustrates this:
Input
!= "a" (A)
!= "b" (B)
!= "c" (C)
A or B or C
a
False
True
True
True
b
True
False
True
True
c
True
True
False
True
d
True
True
True
True
other
True
True
True
True
In other words, unless question1 is some sort of "Schrodinger's variable" that can be all of a, b, and c at the same time, that if statement of yours will never be false.
However, if the subject's favourite sport is football, I'm not sure why you wouldn't just use the much simpler condition below:
if (question1 == "d") {
WriteLine("That is correct");
} else {
WriteLine("That is incorrect try again");
}
That approach (accepting the right answer) seems far easier than what your original code seems to be doing (rejecting all of the the wrong answers).
And, yes, a while loop probably would be better for a quiz scenario, something like the following would be a good start.
I've even added a rudimentary scoring system, because I get bored easily :-)
The points for a question reduce if you answer wrongly: two points for a correct answer first time, one point if you get it right second time, no points otherwise:
int score = 0; // Done once before ALL questions.
int awardPoints;
string answer;
awardPoints = 2; // Done before EACH question.
do {
// Output the question and get an answer.
WriteLine();
WriteLine("What is his favourite sport (x to exit)? ");
WriteLine(" a) Soccer");
WriteLine(" b) Basketball");
WriteLine(" c) Tennis");
WriteLine(" d) Football" );
Write("Your answer: ");
answer = ReadLine();
// Evaluate answer (d is correct here). An x answer
// will produce no output as it assumes you want to
// just exit.
if (answer == "d") {
score += awardPoints;
WriteLine("Correct, you earned {} points, now at {}",
awardPoints, score);
} else if (answer != "x") {
// Incorrect answer. Halve question points so
// user cannot simply keep trying without
// some penalty.
WriteLine("Incorrect, try again");
awardPoints = awardPoints / 2;
}
} while (answer != 'd' && answer != 'x');
// Here, either the correct answer or 'x' was
// given. If 'x', probably want to stop asking
// questions. Otherwise go on to next question.

Please, try this way.
void Main()
{
string question1 = "";
do
{
//Question 1
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("What is his favourite sport? ");
Console.WriteLine("a) Soccer");
Console.WriteLine("b) Basketball ");
Console.WriteLine("c) Tennis ");
Console.WriteLine("d) Football ");
Console.Write("your answer is: ");
question1 = Console.ReadLine();
Console.WriteLine(question1);
if (question1 == "a" || question1 == "b" || question1 == "c")
{
Console.Write("That is incorrect try again");
}
else
{
Console.Write("that is correct");
}
} while (question1 != "q");
}

When you use || operator, as soon as any condition is true, it stops processing rest of the cases and marks the statement as true.
The best way is, to test the correct answer and put rest of the cases in else block and mark them as 'incorrect'
if (question1 == 'correctOption')
{
System.Console.Write("That is correct.");
}
else
{
System.Console.Write("That is incorrect try again");
}

The runtime evaluates from left to right. In case of || it stops at the first true and returns true. If there is nothing which is true then it returns false.
In case of && it stop at the first false and returns false.
The readable code if to check for right answer and say correct and for all others display incorrect. This will also take care of user entering any other value other than "a","b,"c" as well like say "t"

Trying to make quit sequence that only proceeds when correct input is given

i'm having trouble creating a loop that will request user input and if the input is not "Y" or "N" to re-prompt the user to input over and over until they give the correct input.
while (quitOrContinue != "Y"|"N")//cant use "Y"/"N" in the same line, how do I phrase this line?
Console.Write("\nWould you like to process another set of bowling scores?");
Console.WriteLine("\nPress 'Y' to process another set or 'N' to exit the program");
Console.Clear();// this needs to happen if the input to run again is "Y"

Well, for starters, you're not actually taking any input at all from the user. You can use Console.WriteLine to output whatever sort of instructions you want from the user, but you have to actually capture them somehow.
To get input, you'd have to use Console.Read(), and you'd have to use conditional blocks to check their input. You should wrap your code in a while loop that references a sentinel value:
bool userIsDone = false;
Console.Write("\nWould you like to process...");
while (!userIsDone)
{
string userInput = Console.ReadLine();
// ...
if (userInput == "Y")
{
// process another set here
Console.WriteLine("\nWould you like to process...");
}
else if (userInput == "N")
{
// exit your program
}
else
{
Console.WriteLine("That input is invalid.");
}
}
Also, about the code you have above - you should wrap the elements inside loops in { }, and the | is the bitwise OR, not logical or. Logical or (which I'm 99% you want in this situation) is ||, and logical and is &&.

Why not use a loop ?
string input = null;
while((input = Console.ReadLine()) != "Y" || input != "N")
{
Console.WriteLine("Invalid value, please try again:");
}
Here the expression (input = Console.ReadLine()) != "Y" || input != "N" will be evaluated before and each time after the loop runs. It basically reads a line from the input stream and assign it to input variable then checks if it's not Y or N it executes the loop body and evaluates the expression again and ask for input until the condition satisfies.You can use Console.Read method to read one charachter but it returns int so you need to cast it to char.

While or and not equal to not working?

Im quite new to C# and am trying to write a super simple loop
while ((var_app_choice != "Exit") || (var_app_choice != "Test"))
{
//stuff
}
I have a console application where an end user will input a value
If this value is not equal (!=) to Exit OR Test then it should loop.
What am i doing wrong here?
Thanks

If you want to come out of the loop, when the User enters Exit or Test then you need the && operator not ||
while ((var_app_choice != "Exit") && (var_app_choice != "Test"))
{
var_app_choice = Console.ReadLine();
//stuff
}

I think you want and not or...
If the value of var_app_choice is "Test", then the first condition is true and the loop will execute. Similarly, if it's "Exit", then the second condition is true. In other words, you have an infinite loop...

Friend,
Consider I am having a data list as
List dataList = new List() { "Apple", "Microsoft", "exit", "Oracle", "Android" };
int i = 0;
while (dataList[i] != "exit" || dataList[i] != "test")
{
Console.WriteLine(dataList[i]);
i++;
}
You would expect that the ouput should be only Apple and Microsoft. When it encounters "exit" in index 2 it should stop.
What really happens(consider it is verifying "exit") is the first condition fails, which means NotEqualTo Operator works fine. The problem is your OR operator. Since "exit" not equals "test", the condition passed and it further enters into the loop.
Your data must not be equal to "exit" and also not equal to "test".
Think you got the problem. For your information, While(condn){} here you can mention any condition that outputs a boolean(true or false).
Thanks and Correct me if I am wrong.

C# simple IF OR question

Sorry to ask this as I thought I knew the answer, I want to exit the program if userName is greater than 4 characters or userName is not an account called student. However this even if the userName is only 3 characters and is not student I'm still hitting Application.Exit. What am I doing wrong?
if (userName.Length > 4 | userName != "student")
{
Application.Exit();
}
Shame on me :-(

While you should use || instead of |, they will give the same result in this situation. Despite the upvoting of the other answers, changing | to || will not solve your problem.
Your real problem is that the conditions you want to check for will always be true. Either your userName is not student, or it is student and then it is also longer than 4 characters.
When you have a username that is only 3 characters it is not equal to student, therefore the program quits.
From your description of what you expect, I think you mean this:
if (userName.Length > 4 && userName != "student")
{
Application.Exit();
}

You need to use the boolean OR (||) operator instead of the bitwise OR (|)
As I said in my comments though, your logic doesn't necessarily make any sense to me. The way it is writting, the statement will always be true:
If userName is not student, the statement is true and the application exits.
If userName is student, then length > 4 and the statement is true again (which causes an exit).
You could change things to:
if(username.Length > 4 && userName != "student")
{
Application.Exit();
}
Which makes more sense logically, but since I don't know your intent I can't guarantee that it would work the way you want it to.

From looking at your requirement your check for the length of chars is negligable or at least you haven't mentioned the reason why you want to check length of the char. From the example you have provided I would simply check if (userName != "student") I don't see the need for the extra check this is something that can be forced in the UI.

If I am not wrong, you are trying to enter into the if loop when either of the condition is true.
i.e., enter into the if loop
when Length is greater than .
when userName should not be equal to "student"
condition like username = "ABC" is not "student", your condition still right and will enter. It will execute still when userName is equal = "student";
Here You should use AND operator than just OR operator.
if (userName.Length > 4 & userName != "student")
{
Application.Exit();
}
You can also achieve the same result with && operator. & opertor is same as && operator.
when X = false and Y is true; Y will not be evaluated at all. Since X is already false. this is method is also call short-circuit evaluation.

if (userName.Length > 4 || userName.ToLower() != "student")
{
Application.Exit();
}
Try this.