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While loop running infinite

I'm writing the program to receive Int input from user in range of 8 to 12. However, loop goes on to run infinitely if input is less than 8 or greater than 12. Can anyone please guide what I'm doing wrong here?
int numLength;
Console.WriteLine ("Enter a number:");
while(!int.TryParse(Console.ReadLine(), out numLength))
{
Console.WriteLine("Invalid input.");
}
while(true)
{
if((numLength >= 8) && (numLength <= 12))
break;
else
{
Console.WriteLine("Only between 8 and 12.");
}
}

You need to add a 'break' statement after 'Console.writeline' in the 'else' section. Without it, your code is not able to exit the inner while loop if values smaller than 8 and larger than 12 are entered. Secondly, the user has no way of re-entering data if values outside the given range are entered. Here is what you need to do instead.
while(true)
{
Console.WriteLine ("Enter a number:");
while(!int.TryParse(Console.ReadLine(), out numLength))
{
Console.WriteLine("Invalid input.");
}
if((numLength >= 8) && (numLength <= 12))
break;
else
{
Console.WriteLine("Only between 8 and 12.");
}
}

It's because in the case where the input is a valid integer but not between 8 and 12, you do not allow the user to re-enter a number. You would need to do ReadLine() again after you do the print Console.WriteLine("Only between 8 and 12."); but then you'd need to make sure the input is valid again.
I suggest changing the code structure a bit, using a do while and saving the result of ReadLine() to a variable and doing both checks after.
e.g.
int numLength;
bool isValid = false;
bool isRightLength = false;
do
{
Console.WriteLine("Enter a number:");
isValid = int.TryParse(Console.ReadLine(), out numLength);
if (isValid)
{
isRightLength = (numLength >= 8) && (numLength <= 12);
if (!isRightLength)
{
Console.WriteLine("Only between 8 and 12.");
}
}
else
{
isRightLength = false;
Console.WriteLine("Invalid input.");
}
}
while (!isValid || !isRightLength);

How to ignore a line/block of code if the condition is met?

Is there a way to ignore a line/block of code if the condition is met?
I'm doing a C# .NET tutorial, and the application is a number guessing game.
I added a hint option if the user enters a wrong number (else if part):
// While guess is not correct
while (guess != correctNumber)
{
//Get users input
string input = Console.ReadLine();
// Make sure it's a number
if (!int.TryParse(input, out guess))
{
// Print error message
PrintColorMessage(ConsoleColor.Red, "Please use an actual number");
// Keep going
continue;
}
// Cast to int and put in guess
guess = Int32.Parse(input);
// Check if guess is close to correct number
if(guess == correctNumber + 2 || guess == correctNumber - 2)
{
// Tell the user that he is close
PrintColorMessage(ConsoleColor.DarkCyan, "You are close!!");
}
// Match guess to correct number
else if (guess != correctNumber)
{
// Print error message
PrintColorMessage(ConsoleColor.Red, "Wrong number, please try again");
AskForAHint(correctNumber);
}
}
// Print success message
PrintColorMessage(ConsoleColor.Yellow, "You are CORRECT!");
Basically I am asking a user if he wants a hint, and if he writes Y, the hint will be displayed. However, is there an option to display this question only once since this if statement is included in a while loop?
It would be annoying if "Do you want a hint?" question keeps displaying even if the user says Y.
My AskForAHint function:
static void AskForAHint(int num)
{
// Ask user if he wants a hint
Console.WriteLine("Do you want a hint? [Y/N]");
// Take his answer
string ans = Console.ReadLine().ToUpper();
// If the user wants a hint
if (ans == "Y")
{
// First hint number
int beginning = (num - num % 10);
// Second hint number
int finish = beginning + 10;
// Give user a hint
Console.WriteLine("The correct number is somewhere betweer {0} and {1}", beginning, finish);
}
else if (ans == "N")
{
return;
}
}
Thanks

Another way to do it would be to make the number of hints configurable (allowing the caller to specify how many hints they want to let the user ask for), and then keep track of the number of hints given in the method itself.
This would require a slight change to the AskForAHint method, however, since we don't know if the user answered "Y" or "N" to the hint question. Since AskForHint has no return value, we could have it return a bool that indicates how the user responded to the question:
static bool AskForAHint(int num)
{
var answer = GetUserInput("Do you want a hint? [Y/N]: ", ConsoleColor.Yellow);
if (!answer.StartsWith("Y", StringComparison.OrdinalIgnoreCase))
{
return false;
}
var beginning = num - num % 10;
var finish = beginning + 10;
Console.WriteLine($"The correct number is somewhere between {beginning} and {finish}");
return true;
}
Now we can keep track of how many hints the user has received by incrementing a counter in our "Game" method:
// Only ask for a hint if they have any hints (and guesses) remaining
if (hintCount < maxHints && guessCount < maxGuesses)
{
// If they asked for a hint, increase the hint count
if (AskForAHint(correctNumber)) hintCount++;
// If they didn't want a hint, max out hint count so we don't ask again
else hintCount = maxHints;
}
To test out the sample code above, I used this method below, which also allows us to configure how many total guesses the user has, what the min and max values of the range should be, and if they should be given a "directional hint", like "too high!" or "too low!":
private static readonly Random Random = new Random();
private static void PlayGuessingGame(int maxHints = 1, int maxGuesses = 10,
int rangeMin = 1, int rangeMax = 100, bool giveDirectionalHint = true)
{
if (rangeMax < rangeMin) rangeMax = rangeMin;
var correctNumber = Random.Next(rangeMin, rangeMax + 1);
var guessCount = 0;
var hintCount = 0;
WriteMessage("Welcome to the guessing game!", ConsoleColor.White);
WriteMessage("-----------------------------\n", ConsoleColor.White);
WriteMessage($"I'm thinking of a number from {rangeMin} to {rangeMax}. ", ConsoleColor.Green);
WriteMessage("Let's see how many guesses it takes you to guess it!\n", ConsoleColor.Green);
do
{
WriteMessage($"(You have {maxGuesses - guessCount} guesses left)");
var input = GetUserInput("Enter the number I'm thinking of: ", ConsoleColor.White);
int guess;
if (!int.TryParse(input, out guess))
{
WriteMessage("Please enter a whole number", ConsoleColor.Red);
continue;
}
// Only increment guesses if they entered an actual number
guessCount++;
if (guess == correctNumber) break;
if (Math.Abs(guess - correctNumber) == 2)
{
WriteMessage("You are close!!", ConsoleColor.DarkCyan);
}
if (giveDirectionalHint)
{
WriteMessage("Wrong number - too " + (guess < correctNumber ? "low!" : "high!"),
ConsoleColor.Red);
}
else
{
WriteMessage("Wrong number, please try again", ConsoleColor.Red);
}
// Only ask for a hint if they have any hints (and guesses) remaining
if (hintCount < maxHints && guessCount < maxGuesses)
{
// If they asked for a hint, increase the hint count
if (AskForAHint(correctNumber)) hintCount++;
// If they didn't want a hint, max out hint count so we don't ask again
else hintCount = maxHints;
}
} while (guessCount < maxGuesses);
WriteMessage("You are CORRECT!", ConsoleColor.Yellow);
GetKeyFromUser("\nDone! Press any key to exit...");
}
This uses the helper functions:
public static void WriteMessage(string message, ConsoleColor color = ConsoleColor.Gray)
{
Console.ForegroundColor = color;
Console.WriteLine(message);
Console.ResetColor();
}
private static string GetUserInput(string prompt, ConsoleColor color = ConsoleColor.Gray)
{
Console.ForegroundColor = color;
Console.Write(prompt);
Console.ResetColor();
return Console.ReadLine();
}
Output
You can see in the output below, I was only given a single hint. However that, combined with the directional hints, made the game easy to win:

I think you can do an "if" with a counter.
Try It
Int cont = 0; //global
// While guess is not correct
while (guess != correctNumber)
{
//Get users input
string input = Console.ReadLine();
// Make sure it's a number
if (!int.TryParse(input, out guess))
{
// Print error message
PrintColorMessage(ConsoleColor.Red, "Please use an actual number");
// Keep going
continue;
}
// Cast to int and put in guess
guess = Int32.Parse(input);
// Check if guess is close to correct number
if(guess == correctNumber + 2 || guess == correctNumber - 2)
{
// Tell the user that he is close
PrintColorMessage(ConsoleColor.DarkCyan, "You are close!!");
}
// Match guess to correct number
else if (guess != correctNumber)
{
// Print error message
PrintColorMessage(ConsoleColor.Red, "Wrong number, please try again");
if(cont == 0){
AskForAHint(correctNumber);
}
}
}
// Print success message
PrintColorMessage(ConsoleColor.Yellow, "You are CORRECT!");
And in the function add
static void AskForAHint(int num)
{
// Ask user if he wants a hint
Console.WriteLine("Do you want a hint? [Y/N]");
// Take his answer
string ans = Console.ReadLine().ToUpper();
// If the user wants a hint
if (ans == "Y")
{
cont = 1;
// First hint number
int beginning = (num - num % 10);
// Second hint number
int finish = beginning + 10;
// Give user a hint
Console.WriteLine("The correct number is somewhere betweer {0} and {1}", beginning, finish);
}
else if (ans == "N")
{
return;
}
}

Use a Member Variable Boolean, its similar to how you can avoid recursive calls.
private bool alreadyHinted = false;
static void AskForAHint(int num)
{
if (alreadyHinted) return;
alreadyHinted = true;
At some point you will need to set alreadyHinted back to false;

How do I allow the user more attempts as opposed to just restarting the game after catching a format exception?

So, I'm building this little guessing game and I recently added a try/catch to stop the console from crashing if the user inputted a wrong character (besides numbers of course). Right now it works well but it restarts the entire game, I've tried to just have the catch re-run the script starting at the "for" loop, but it breaks and the random number originally generated doesn't match.
public static void StartGame()
{
Console.Clear();
Random ran = new Random();
decimal returnValue = (ran.Next(1, 100));
Console.WriteLine("Welcome to my guessing game. I'm thinking of a number between 1 and 100, can you guess it?");
Console.WriteLine("Hint: 'Way too off' means you're greater than 25 from the answer!");
try
{
for (int guessnumber = 1; guessnumber < 6; guessnumber++)
{
var Guess = Convert.ToInt32(Console.ReadLine());
//The Guess variable is simply whatever the user inputs, which is read and used by the for loop each time it is inputed.
if (Guess == returnValue)
{
Console.WriteLine("Well done!");
Console.ReadKey();
Game.NewGame();
}
else if (Guess < returnValue)
{
Console.WriteLine("Guess higher!");
}
else if (Guess > returnValue)
{
Console.WriteLine("Guess lower!");
}
if (guessnumber == 5)
{
Console.WriteLine($"The correct answer was {returnValue}");
Console.ReadKey();
Game.NewGame();
//This if statement activates when the "guessnumber" counter has reached 5, in which case it will tell the user the correct answer, and end with a return statement.
}
//result is the absolute value of
decimal result = Math.Abs(returnValue - Guess);
if (result > 25)
Console.WriteLine("Way too off!");
if (result < 5)
{
Console.WriteLine("Very close!!");
}
if (result < 2)
{
Console.WriteLine("RED HOT!!!");
}
}
}
catch (System.FormatException)
{
Console.WriteLine("Incorrect character inputted, restarting game. . .");
System.Threading.Thread.Sleep(2000);
StartGame();
}
}
public static void NewGame()
{
Console.Clear();
string input = " ";
Console.WriteLine("Game over, would you like to play again? Y/N");
input = Console.ReadLine();
input = input.ToUpper();
if (input == "Y")
{
Console.WriteLine("Ok! Re-Initializing game...");
StartGame();
}
else
{
System.Environment.Exit(0);
}
}
}
}

As another answer stated, you can just move your try/catch inside the for loop, so the loop continues.
But you really shouldn't be relying on exception handing for something that isn't exceptional, like parsing user input.
Instead, we can use the int.TryParse method to try to parse a string to an int. The nice thing about this method is that it returns true if the parse was successful, and it sets an out parameter to the parsed value.
We can also put it in it's own method that takes in a string to be used to prompt the user, which makes the code more reusable:
public static int GetIntFromUser(string prompt)
{
int result;
bool askedOnce = false;
do
{
if (askedOnce) Console.WriteLine("Invalid input, please try again.");
Console.Write(prompt);
askedOnce = true;
} while (!int.TryParse(Console.ReadLine(), out result));
return result;
}
Now our main code is greatly simplified (also notice that the Random instance should be a class field, not created on every call to StartGame, and notice that the upper bound specified in the call to ran.Next is exclusive, so if you want to include 100 as a possible answer, make the max value 101):
private static Random ran = new Random();
public static void StartGame()
{
Console.Clear();
int randomNumber = ran.Next(1, 101);
Console.WriteLine("Welcome to my guessing game");
Console.WriteLine("I'm thinking of a number between 1 and 100, can you guess it?");
for (int guessCount = 1; guessCount < 6; guessCount++)
{
var guess = GetIntFromUser($"Guess a number (try #{guessCount}): ");
if (guess == randomNumber)
{
Console.WriteLine("Well done!");
Console.ReadKey();
Game.NewGame();
}
else if (guessCount == 5)
{
Console.WriteLine("That was your last guess.");
Console.WriteLine($"The correct answer was: {randomNumber}.");
Console.ReadKey();
Game.NewGame();
}
else
{
decimal result = Math.Abs(randomNumber - guess);
if (result > 25) Console.Write("You're way off! ");
else if (result < 5) Console.Write("Very close!! ");
else if (result < 2) Console.WriteLine("You're RED HOT!!! ");
Console.WriteLine(guess < randomNumber ? "Guess higher!" : "Guess lower!");
}
}
}

Move the Try Catch handling inside for loop. What this does is, that exceptions are handled during each guess iteration.
What you had originally was exception handling for all iterations.
Also, Dont call the StartGame Function again in your catch block. You want to allow 6 (per the for loop) Guesses and not Infinite.
Ex:
for (int guessnumber = 1; guessnumber < 6; guessnumber++)
{
try
{
}
catch (System.FormatException)
{
}
}

The simple answer is as follows:
You don't control application flow with exception handling. Catching exceptions are for exceptional circumstances, a user getting input wrong isn't exceptional... it's guaranteed.
Never ever ever ever ever (+1000) use Convert.... or int.Parse to take user input... Users make mistakes all the time, use the TryParse type methods instead, they return a bool to say if the data was successfully parsed so you can then deal with it.
Eg
var success = int.TryParse(Console.ReadLine(), out var guess);
However, you can take it one step further, and add a loop (add pepper and salt to taste)
int guess = 0;
while(!int.TryParse(Console.ReadLine(), out guess))
Console.WriteLine("Omg you had one job, just enter a number");
Additional Resources
Int32.TryParse Method
Converts the string representation of a number to its 32-bit signed
integer equivalent. A return value indicates whether the operation
succeeded.

cannot figure out while random number generator game is not working c#

I am programming a game that generates a random number and then has the user try to guess the number when the user inputs a number the program will respond with either too high or too low depending on the number generated.The problem I am having is that the loop will just keep executing and the program will not take another user input if the number is incorrect.I have tried using different types of loops like a do while and for loop but keep getting the same problem I feel as though I am missing something simple or making a simple mistake thanks
string usernumber;
Random rnd = new Random();
int value = rnd.Next(1,50); //generates a random number upto 50
int guess = 0;
Console.WriteLine("please enter a number"); //asks for and takes user input
usernumber = Console.ReadLine();//stores user input
guess = Convert.ToInt32(usernumber);
while (guess != value) //this stands for not equals to
{
//guess = Convert.ToInt32(usernumber);
if (value > guess)
{
Console.WriteLine("too high");
}
else if (value < guess)
{
Console.WriteLine("too low");
}
else if (value == guess)
{
Console.WriteLine("bang on the answer was" + value);
}
else
{
Console.WriteLine("errrrrrrrrr");
}
}
Thread.Sleep(2000); //delays the program closing for a bit

You can use this corrected and refactored to have more explicit variables names.
We add 1 to 50 because the Random.Next last parameter is the upper bound excluded.
We use a do...while loop to have a concise algorithm.
We use int.TryParse to get the int from the user. This method returns false and sets the value to 0 in case of conversion error instead of an exception.
We use Console.ReadKey instead of Thread.Sleep, that is more UX friendly.
var random = new Random();
int numberTarget = random.Next(1, 50 + 1);
int numberUser;
do
{
Console.Write("Please enter a number between 1 and 50: ");
if ( int.TryParse(Console.ReadLine(), out numberUser) )
{
if ( numberUser > numberTarget )
{
Console.WriteLine("Too high, retry.");
}
else
if ( numberUser < numberTarget )
{
Console.WriteLine("Too low, retry.");
}
else
{
Console.WriteLine($"Bang on the answer was {numberTarget}.");
}
}
else
{
Console.WriteLine("You didn't enter a valid number, retry.");
}
}
while ( numberUser != numberTarget );
Console.WriteLine("Press a key to exit.");
Console.ReadKey();

In your while loop, you forgot to make another ReadLine.
while (guess != value) //this stands for not equals to
{
if (value > guess)
{
Console.WriteLine("too high");
guess = Convert.ToInt32(Console.ReadLine());
}
else if (value < guess)
{
Console.WriteLine("too low");
guess = Convert.ToInt32(Console.ReadLine());
}
else if (value == guess)
{
Console.WriteLine("bang on the answer was" + value);
}
else
{
Console.WriteLine("errrrrrrrrr");
}
}

How can I make my program stop reading user input when no input is given?

I am trying to make a program that calculates some specific data from numbers given by a user.
In this example, my program counts amount of numbers in range (10,103) that are divisible by 2, and amount of numbers that are in range (15,50) divisible by 3 within numbers given by user.
On this stage, my program gives the results, when 10 numbers are given (as I specified it in the loop). How can I make my program stop reading numbers and give the results when user imputs an empty line no matter if he, entered 5 or 100 numbers before?
Here is my code, as it looks for now:
using System;
namespace Program1
{
class MainClass
{
public static void Main (string[] args)
{
int input10_103_div_2 = 0;
int input15_50_div_3 = 0;
for (int i = 0; i < 10; i++)
{
string input = Console.ReadLine ();
double xinput = double.Parse (input);
if (xinput > 10 && xinput <= 103 && (xinput % 2) == 0)
{
input10_103_div_2++;
}
if (xinput > 15 && xinput < 50 && (xinput % 3) == 0)
{
input15_50_div_3++;
}
}
Console.WriteLine ("Amount of numbers in range (10,103) divisible by 2: " + input10_103_div_2);
Console.WriteLine ("Amount of numbers in range (15,50) divisible by 3: " + input15_50_div_3);
}
}
}

instead of for, do:
string input = Console.ReadLine();
while(input != String.Empty)
{
//do things
input = Console.ReadLine();
}
if you're trying to allow any number of inputs. Or
if(input == "")
break;
if you want the for loop

Change your loop to go forever and break out of the loop when the string is empty:
for (;;)
{
string input = Console.ReadLine ();
if (String.IsNullOrEmpty(input))
{
break;
}
// rest of code inside loop goes here
}

If you want to restructure the loop, you can use a do while loop:
string input;
do{
input = Console.ReadLine();
//stuff
} while(!string.IsNullOrEmpty(input));
If you just want to be able to break early:
string input = Console.ReadLine ();
if(string.IsNullOrEmpty(str))
break;
double xinput = double.Parse (input);