I know this is more than likely very stupid, but my teacher and I cannot seem to get the <cctype> header file to work properly so I can figure out a way to handle the error if someone presses a key on the keyboard since if they do when they are prompted, the program gets all screwed up.

Code:
#include <iostream.h>
#include <iomanip.h>
#include <stdlib.h>
#include <conio.h>
#include <cctype.h>
#include <windows.h>
#include <time.h>
#include <string.h>



void Start();			//sets Start() as a function to be called later in the program for a 
						//specific piece of code to be called upon
void GetResults();		//set GetResults() as a function to be called later in the program for a
						//specific piece of code to be called upon

int j, guess, i, max, Status, perfect;	//declares these as interger variables to be used throughout 
								        //the program

char c, ch, string[100];				//declares c to be used as a char variable throughout the program


int main()
{
	//This will set the Title bar text
    Status = SetConsoleTitle("Jackpot -:::- Can You Guess The Number? ");

	HANDLE hOut;	//declared hOut as being a type of variable used to be called later 
					//in the program			
    hOut = GetStdHandle(STD_OUTPUT_HANDLE);

	//This will set the background color and the text color
	SetConsoleTextAttribute(hOut,
                            FOREGROUND_RED |
							BACKGROUND_GREEN|
							BACKGROUND_INTENSITY|
							FOREGROUND_INTENSITY);
	//This part of the Program will display information about the program to the user before
	//they begin the game
	cout << setw(45) << "-_- Jackpot -_-" << setw(35) << " \n";
    cout << "The object of the game is to guess the number according to the level you pick.\n";
    cout << "You will have 10 guesses to to get this number.\n";
    cout << "The game will tell you if you are guessing either too high or too low, and in \n";
	cout << "the end will tell you the correct number if you don't guess it.\n\n";
    Start();	//calls the Start() function

    return 0;	//will return control to the computer after the Start() function is executed
}

void Start()	//begins the function Start() which was declared earlier in the program
{
	//Asks the user to select their level of difficulty
    cout << "Select your level of difficulty:\n"; 
    cout << "1 : Novice (0-100)\n";
    cout << "2 : Intermediate (0-500)\n";
    cout << "3 : Expert (0-1000)\n\n";
    cout << "If you would like to quit press another key and then press enter\n";
    cin  >> c;			//Accepts user input and declares it to the c variable
    cout << "\n";
    switch (c)

		{
        case '1' : max = 100; // the random number will be between 0 and 100
        break;
        case '2' : max = 500; // the random number will be between 0 and 500
        break;
        case '3' : max = 1000;// the random number will be between 0 and 1000
        break;
        default  : exit(0);   // exits the program if the user enters something other than 1-3
        break;
		}
    guess = 10;		  // number of guesses the player has
    srand( (unsigned)time( NULL ) ); 
    j = rand() % max; // lets the computer create a random number then turns 
					  // that number into a whole number
    GetResults();
}
void GetResults()
{


	{


    if (guess <= 0)		//this will occur if the player runs out of life
	{
        cout << "How did you not know that the number was " << j << "?\n";
		cout << "You can either play again or quit now by entering a letter and enter.\n\n";
        Start();		//Repeats the Start() function if this if statement is true
    }
		
    cout << "Enter your guess: " << j << endl; //Prompts the user for their guess
    cin  >> i;		// accepts the user's guess

	
	if (guess == 10 && i == j)//displays this if they only used one guess to get the
							  //correct number
	{
		cout << "Wow, you are a pure genius, amazing, one try! Or maybe you're just lucky...\n\n";
		Start(); 
	}

	if (guess == 9 && i == j)//displays this if they only used two guesses to get the 
							 //correct number
	{
		cout << "Well, it only took two tries, not too bad...\n\n";
		Start(); 
	}
	if (guess == 8 && i == j)//displays this if they only used three guesses to get the
							 //correct number
	{
		cout << "Three tries, that might be average...\n\n";
		Start(); 
	}
	if (guess == 7 && i == j)//displays this if they used four guesses to get the\
							 //correct number
	{
		cout << "You must be a little kid!\n\n";
		Start(); 
	}
	if (guess <=6 && guess >= 3 && i == j)//displays this if the user used between five
										  //and eight guesses to get the oorrect number
	{
		cout << "Ummmm... is this game too difficult for you?  That's too many tries.\n\n";
		Start(); 
	}
	if (guess <= 3 && i == j)//displays this if the user has less than 3 guesses when they
							 //get the correct number
	{
		cout << "Would you like me to make a new version for you, one with smaller numbers?\n\n";
		Start(); 
	}

	if (i == max + 1)	  // if statement that will execute if the player wants to be funny and 
						  // enter one number higher than their selected range of numbers
	{
		cout << "Now, I know you think you're funny, but enter a valid number.\n";
		GetResults();	//Repeats the GetResults() function if the user enters one number over 
	}					//the max

    else if (i >= max + 2 || i < 0) // if the player enters an invalid number
	{								// this if statement will be executed
        cout << "Error Number 1:Your number is not within the level of difficulty you picked.\n";
        GetResults();	//Will pick up the GetResults() function if the user enters an 
    }					//invalid entry

    else if (i > j)		// this if statement will be executed if the user guesses too high
	{
        cout << "You guessed too high, try a smaller number.\n";
        guess = guess - 1; // subtracts one guess from their previous total if they guess wrong
        //Shows the user their remaining amount of guesses
		cout << "Number of remaining guesses: " << guess << "\n\n";
        GetResults();	//Starts the GetResults() function over after the user makes an 
    }					//incorrect guess

    else if (i < j)		// this if statement will be executed if the user guesses too low
	{
        cout << "You guessed too low, try a larger number.\n";
        guess = guess - 1; // subtracts one guess from their previous total if they guess wrong
        //Shows the user their remaining amount of guesses
		cout << "Number of remaining guesses: " << guess << "\n\n"; 
        GetResults();	//Starts the GetResults() function over after the user makes an 
    }					//incorrect guess
	
}
}