We Keep Coding

How do I repeat a question in a switch case

I'm trying to make a question repeat if the input isn't right. Here's the code:
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
Boolean input = true;
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
break;
case "bob":
Console.WriteLine("you chose a bob");
break;
}
How do I make it if it isn't one of the two answers it reasks the question?

Use the default case.
If none of the cases in a switch statement match, the default case runs.
Here's an example.
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
switch (userInput)
{
case "joe":
// ...
break;
case "bob":
// ...
break;
default:
// This runs if userInput is neither "joe" nor "bob"
}
Then you can make a method that writes choose a name to the console, takes the user's input, and runs the switch statement - and the default case would call the same method.
void GetName()
{
// Write "choose a name" to the console
// Take the user's input
switch (userInput)
{
case "joe":
// ...
break;
case "bob":
// ...
break;
default:
GetName();
return;
}
}

You need a loop (either while or do-while) to repeat the iteration but not a switch-case.
While switch-case is used to control the flag (isCorrectInput) that stops the loop.
bool isCorrectInput = false;
do
{
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
isCorrectInput = true;
break;
case "bob":
Console.WriteLine("you chose a bob");
isCorrectInput = true;
break;
}
} while (!isCorrectInput);
Reference
Iteration statement

You should use a bool variable, that will determine whether you need to repeat the logic or not. Combine it with a loop and you get this:
bool keepAsking = true;
while (keepAsking)
{
Console.WriteLine("choose a name");
string userInput = Console.ReadLine();
Boolean input = true;
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
keepAsking = false;
break;
case "bob":
Console.WriteLine("you chose a bob");
keepAsking= false;
break;
}
}

You can try something like this. BUt you need to slightly change your code.
class XYZ
{
static void Main(string[] args)
{
GetData()
}
}
static void GetData()
{
string userInput = Console.ReadLine();
checkcondition(userInput);
}
static void checkcondition(userInput)
{
switch (userInput)
{
case "joe":
Console.WriteLine("you chose a joe");
break;
case "bob":
Console.WriteLine("you chose a bob");
break;
default:
GetData();
break;
}
}

You can also achieve the same results using a smaller code but with a while loop instead of switch statement
while(true){
Console.Write("Choose a Name: ");
var name = Console.ReadLine().ToLower();
if(name == "joe" || name == "bob"){
Console.WriteLine("You chose a " + name + "!");
break;
}else{
Console.WriteLine("Invalid Selection, Try Again");
}
}

How to rerun a code again in switch statement

Objective: Request users to input yes or no again when they type "idk" until they reply yes or no, how to rerun the ask and ans above?
Requirement: Not to use boolean.
static void Main(string[] args)
{
string ask = "Yes or No?";
Console.WriteLine(ask);
string ans = Console.ReadLine();
switch(ans)
{
case "yes":
yes();
break;
case "no":
no();
break;
case "idk":
//run "ask" again
}
}

Hmmm.. Normally you would use booleans and loop while the boolean is still true and set it to false when you get what you want.
But if you want to avoid booleans you can use an infinite loop and just return out of the function you are in when you are done:
class Program
{
static void Main(string[] args)
{
string ask = "Yes or No?";
for (;;)
{
Console.WriteLine(ask);
string ans = Console.ReadLine();
switch(ans.ToLower())
{
case "yes":
yes();
return;
case "no":
no();
return;
}
}
}
static void yes() => Console.WriteLine("Yes selected");
static void no() => Console.WriteLine("No selected");
}

I will be suggesting you use a do-while loop rather then goto statment
static void Main(string[] args)
{
NotFound:
string ask = "Yes or No?";
Console.WriteLine(ask);
string ans = Console.ReadLine();
switch (ans)
{
case "yes":
yes();
break;
case "no":
no();
break;
case "idk":
goto NotFound;
}
}
private static void no()
{
}
private static void yes()
{
}

switch(exp)
{
case "+":
Console.WriteLine("Enter Yor Number");
int PlusA = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Enter Yor Number");
int PlusB = Convert.ToInt32(Console.ReadLine());
Console.WriteLine("Answer =");
Console.WriteLine(PlusA + PlusB);
One more question I want to make a plus calculator, I want to let the user type more then 2 numbers, until they type the symbol ; how to do that?

c# endless method switch loop. Trying to execute the method and end it with a return; statement but it loops back to the begining of the method

I am having an issue where my method is running endlessly i have tested and it runs through the do while loop fine and terminates, but despite it having a return; statement. My program is not ending the method and returning to main.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp2
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Hello, What would you like to do?\n1. add a phonebook entry.\n2. search for a specific phonebook entry.\n3. see all phonebook entries.\n4. quit.");
var choice = Console.ReadLine();
int Choice;
var END = "";
do
{
if (int.TryParse(choice, out Choice) && Choice >= 1 && Choice <= 4)
{
switch (Choice)
{
case 1:
addName();
Choice = 0;
break;
case 2:
findName();
break;
case 3:
seeNames();
break;
case 4:
END = "123898761hgasdbfasd";
break;
default:
Console.WriteLine("Hello, What would you like to do?\n1. add a entry.\n2. search for a specific entry.\n3. see all entries.\n4. quit.");
break;
}
}
else { Console.WriteLine("Hello, What would you like to do?\n1. add a entry.\n2. search for a specific entry.\n3. see all entries.\n4. quit.");
choice = Console.ReadLine();
}
}while(END != "123898761hgasdbfasd");
}
private static void seeNames()
{
throw new NotImplementedException();
}
private static void findName()
{
throw new NotImplementedException();
}
private static void addName()
{
int place = 1,end = 0;
string name = null, address = null, numer = null;
do {
switch (place)
{
case 1:
Console.WriteLine("What name would you like to add?");
var User = Console.ReadLine();
Console.WriteLine("You entered {0} is that right?", User);
name = User;
User = Console.ReadLine();
if (User == "y" || User == "Y") { place = 2; }
else { place = 1; }
break;
case 2:
Console.WriteLine("What address would you like to add?");
User = Console.ReadLine();
address = User;
Console.WriteLine("You entered {0} is that right?", User);
User = Console.ReadLine();
if (User == "y" || User == "Y") { place = 3; } else { place = 2; }
break;
case 3:
Console.WriteLine("What phone number would you like to add?");
User = Console.ReadLine();
Console.WriteLine("You entered {0} is that right?", User);
numer = User;
User = Console.ReadLine();
if (User == "y" || User == "Y") { place = 4; } else { place = 3; }
break;
case 4:
using (System.IO.StreamWriter file = new System.IO.StreamWriter("Addressbook.txt", true))
{ file.WriteLine("Name : {0} Address: {1} Phone-Numer: {2}", name, address, numer); file.Close(); }
Console.WriteLine("Would you like to subbmit another entry?");
User = Console.ReadLine();
if (User == "y" || User == "Y") { place = 1; }
else { end = 5; return; }
break;
default:
break;
}
} while (end != 5);
return;
}
}
}
After reaching place 4 and telling the program i do not want to input another address it loops back and ask for another name. I cant seem to break this loop and cause the program to go back to the main program(main is a 4 choice menu that call other methods.)

Loop for char not working

So, I am attempting to make a loop where if someone enters a char it will execute. If it is wrong it will will display not an option. If I put an Else {Console.WriteLine("Not an option") at the end of the the "end" after my Array() method, it doesn't work either.
So, I am not completely sure of what I am doing. Does this even require a loop? As I would imagine it does to work? Any suggestions would be wonderful.
class Program
{
static void Main(string[] args)
{
string _a = "";
constructor dick = new constructor();
Console.WriteLine("Enter C for constructor, M for method, A for an array...");
Console.WriteLine("Please reference source code to have full details and understanding...");
while (_a.ToUpper() == "C" || "M" || "A")
{
_a = Console.ReadLine();
if (_a.ToUpper() == "C")
{
Console.WriteLine(dick.a);
}
if (_a.ToUpper() == "M")
{
Shit();
}
if (_a.ToUpper() == "A")
{
Array();
}
}
}
public class constructor
{
public string a = "This is a constructor!";
}
static public void Shit()
{
string b = "This is a method!";
Console.WriteLine(b);
}
static public void Array()
{
Console.WriteLine("\nHow large of an array?\n");
string sSize = Console.ReadLine();
int arraySize = Convert.ToInt32(sSize);
int[] size = new int[arraySize];
Random rd = new Random();
Console.WriteLine();
for (int i = 0; i < arraySize; i++)
{
size[i] = rd.Next(arraySize);
Console.WriteLine(size[i].ToString());
}
}
}
}

instead of this:
while (_a.ToUpper() == "C" || "M" || "A")
Define a bool variable and:
bool control = true;
while (control)
{
_a = Console.ReadKey();
var character = _a.KeyChar.ToString().ToUpper();
switch (character)
{
case "C":
Console.WriteLine(dick.a);
control = false;
break;
case "M":
control = false;
Shit();
break;
case "A":
control = false;
Array();
break;
default:
Console.WriteLine("You entered wrong character");
break;
}
}
If you want to force user to enter a correct character, yes you need a loop.And use Console.ReadKey instead of Console.ReadLine if the input is just one character

C# switch statement validation

I was wondering if there was a way to do something like this in C#:
some loop here
{
Console.WriteLine("Please enter a or b");
switch (Console.ReadLine().ToLower())
{
case "a":
//some code here
break;
case "b":
//some code here
break;
default:
Console.WriteLine("Error, enter a or b");
repeat loop
}
}
It's probably a stupid question but something like that would be greatly beneficial to my assignment.

Why not. Run a while loop that exists only when a or b is entered.
bool condition = false;
Console.WriteLine("Please enter a or b");
string str = string.Empty;
while (!condition)
{
str = Console.ReadLine().ToLower();
switch (str)
{
case "a":
//some code here
condition = true;
break;
case "b":
//some code here
condition = true;
break;
default:
Console.WriteLine("Error, enter a or b");
break;
}
}
Console.WriteLine("You have entered {0} ", str);
Console.ReadLine();

What about something like this?
var acceptedValues = new List<string>()
{
"a",
"b",
};
Console.WriteLine("Please enter {0}", string.Join("or", acceptedValues));
var enteredValue = string.Empty;
do
{
enteredValue = Console.ReadLine().ToLower();
} while (!acceptedValues.Contains(enteredValue));