New Problem [Beginner]

[Vintik]

Hi, I got another problem with my code? I have a small guessing game I made. You guess a number 1-100, and it tells you whether its too high or too low.

Once you guess the number it tells you how many tries it took you to guess the number. But I found a bug where if you type in an invalid character the program just goes haywire.

First off here's my code

// Guess My Number
// The classic number guessing game

#include <iostream>
#include <cstdlib>
#include <ctime>
#include <limits>

using namespace std;

int main()
{
	srand(time(0)); // seed random number generator 

	int upTo

	int theNumber = rand() % 100 + 1; // random number between 1 and 100
	int tries = 0, guess;
    
	cout << "\tWelcome to Guess My Number\n\n";

	do
	{
		cout << "Enter a guess: ";
		cin >> guess;
		++tries;

//		if ((guess >=100) && (guess <= 0))    
//		{
//		
//		  while ((guess >=100) && (guess <= 0))
//		  {
//		  cout << "Invalid Response\n";
//		  cout << "Enter another guess: ";
//		  cin >> guess;

//      };
     };

		if (guess > theNumber)
			cout << "Too high!\n\n";

		if (guess < theNumber)
			cout << "Too low!\n\n";
			
	
	
    } while (guess != theNumber);

	cout << "\nThat's it! You got it in " << tries << " guesses!\n";
	cin.ignore(numeric_limits<streamsize>::max(), '\n');
    cin.get();
    return 0;
}

The commented part in the middle was my idea of a solution. I couldn't find a way to fix a invalid type input, so I first set out to find a way to fix an input of lets say 105. So I got an idea, but then it would get the number of tries wrong, then I tried something else and it would always ask for a second input even if the first was correct.

If someone could help me with this problem, I'd appreciate it.

Thanks,
-Vic

[swoopy]

		if ((guess >=100) && (guess <= 0))    
		{
		
		  while ((guess >=100) && (guess <= 0))

Instead of AND, I think you want OR here:

		if ((guess >100) || (guess <= 0))    
		{
		
		  while ((guess >100) || (guess <= 0))

Also for between 1 and 100, use > versus >=.

[Daved]

Check the return value of operator >>. If it is false, then you must clear the fail state. This is why the program goes haywire, because cin is in a fail state when somebody types in an illegal character. Here's an exaple of how to check for a legal number:

while (!(cin >> guess) || guess < 1 || guess > 100)
{
   cin.clear();
   cin.ignore(numeric_limits<streamsize>::max(), '\n');
   cout << "Invalid Response\n";
   cout << "Enter another guess: ";
}

[Vintik]

Is there a way to check for input type?

I'd like to solve my first problem with an input of a character for example. So could I for example have some sort of way to say:

 		if ((guess >100) || (guess <= 0) || (guess ! int)) //Need a way to have || (guess ! int), I want it to check if the input was a number or a letter. Thanks
		{
		
		  while ((guess >100) || (guess <= 0))
		  {
		  
		  cout << "Invalid Response\n";
		  cout << "Enter another guess: ";
		  cin >> guess;
		  };
};

As I said in the comment: Need a way to have

 || (guess ! int)

, I want it to check if the input was a number or a letter. Thanks.

[Dave_Sinkula]

Need a way to have

 || (guess ! int)

, I want it to check if the input was a number or a letter. Thanks.

Read input as a string, then attempt to convert it to a number; if it fails to convert, it is not a number.

#include <iostream>
#include <string>
#include <sstream>
#include <ctime>
#include <limits>
using namespace std;

int main()
{
   srand(time(0)); // seed random number generator 

   int theNumber = rand() % 100 + 1; // random number between 1 and 100
   int tries = 0, guess;

   string line;

   cout << "\tWelcome to Guess My Number\n\n";
   do
   {
      cout << "Enter a guess: ";
      if ( getline(cin, line) )
      {
         istringstream oss(line);
         if ( !(oss >> guess) )
         {
            cout << "Guess a number\n";
            continue;
         }
         if ( guess < 1 || guess > 100 )
         {
            cout << "Guess a number from 1-100\n";
            continue;
         }
         ++tries;
         if ( guess > theNumber )
         {
            cout << "Too high!\n\n";
         }
         else if ( guess < theNumber )
         {
            cout << "Too low!\n\n";
         }
      }
   } while ( guess != theNumber );

   cout << "\nThat's it! You got it in " << tries << " guesses!\n";
   cin.get();
   return 0;
}

/* my output
	Welcome to Guess My Number

Enter a guess: four
Guess a number
Enter a guess: 50
Too low!

Enter a guess: 
Guess a number
Enter a guess: -1
Guess a number from 1-100
Enter a guess: 75
Too low!

Enter a guess: 90
Too low!

Enter a guess: 95
Too low!

Enter a guess: 99
Too high!

Enter a guess: 98
Too high!

Enter a guess: 97

That's it! You got it in 7 guesses!
*/

[Daved]

>> Is there a way to check for input type?

Is there something wrong with the code I posted? It will enter the loop if the user enters a character instead of an int. Basically, anything the user types that doesn't fit into the guess variable (which is an int) will make (cin >> guess) return false. The extra stuff is to clear the error caused by the character so you can use cin again.

Reading in as a string and parsing is a good way to go if you want that extra control.