Help!!!, snake game

[LazyShadows]

i am newbie to cpp and is wondering if you pro programmers could help me sort this problem out . i do not know how to add a continues level in snake program like chaning to level 3 , 4 ,5 and so on after it reach a certain score and also how to increase the speed of the snake after the level .. this is the code ,its just some guy's code on the internet and i made a few modification for it .. pls help me

  #include "stdafx.h"
#include <conio.h>
#include <iostream>

using namespace std;
bool gameOver;
const int width = 20;
const int height = 20;
int x, y, fruitX, fruitY, score, level;
int tailX[100], tailY[100];
int nTail;
enum eDirecton { STOP = 0, LEFT, RIGHT, UP, DOWN};
eDirecton dir; 

void Setup(){
	gameOver = false;
	dir = STOP;
	x = width / 2;
	y = height / 2;
	fruitX =  rand() % width;
	fruitY = rand() % height;
	score = 0;
	level = 1;
}
void Draw ()
{
	system("cls");
	for (int i = 0; i < width+2; i++)
		cout << "X";
	cout << endl;
	
	for (int i = 0; i < height; i++)
	{
		for (int j = 0; j < width; j++)
		{
		     if (j == 0)
				 cout << "X";
			if (i == y && j == x)
				cout << "0";
			else if ( i== fruitY && j == fruitX)
				cout << "M";
			else
			{
			bool print = false; 
			for (int k = 0; k < nTail; k++)
			{
				
			    if (tailX[k] == j && tailY[k] == i)
				{
			         cout << "o";
					 print = true;
				}
			}
            if (!print)
				 cout << " ";
			}
			
			if (j == width -1 )
				 cout << "X";
		}
		cout << endl;
	}
	
	for (int i = 0; i < width+2; i++)
		cout << "X";
	cout << endl;
	cout << "score:" << score << endl;
	cout << "level:" << level <<endl;

	
}
void Input()
{
	if (_kbhit())
	{
		switch (_getch())
		{
		case 'a':
			dir = LEFT;
			break; 
		case 'd':
			dir = RIGHT;
			break;
		case 'w':
			dir = UP;
			break;
		case 's':
			dir = DOWN;
			break;
		case 'x':
			gameOver = true;
			break;
			
		}

	}
}
void Logic()
{
	int prevX = tailX[0];
	int prevY = tailY[0];
	int prev2X, prev2Y;
	tailX[0] = x;
	tailY[0] = y;
	for (int i = 1; i < nTail; i++)
	{
	   prev2X = tailX[i];
	   prev2Y = tailY[i];
	   tailX[i] = prevX;
	   tailY[i] = prevY;
	   prevX = prev2X;
	   prevY = prev2Y;
	}

	switch (dir)
	{
	case LEFT:
		x--;
		break;
	case RIGHT:
		x++;
		break;
	case UP:
		y--;
		break;
	case DOWN:
		y++;
		break;
	default:
		break;
	}
    if (x > width || x < 0 || y > height || y < 0)
    gameOver = true;
	for (int i = 0; i < nTail; i++)
    if (tailX[i] == x && tailY[i] == y)
		gameOver = true;
	
	if (x == fruitX && y == fruitY)
	{
	    score += 10;
	    fruitX =  rand() % width;
		fruitY = rand() % height;  
		nTail++;
		
	if ( score == 80 )	
	{ 
	  level += 1;
	  fruitX =  rand() % width;
	  fruitY = rand() % height;  
	  nTail++;
   }
	
  }

}



int main()
{
	cout << "Welcome to Snake Game created by group 4 " << endl;
	cout << endl;
	cout << "Instruction:" << endl;
	cout << "use the follwing keys to move your snake:" << endl;
	cout << "w = forward" << endl;
	cout <<	"s = backward"  << endl;
    cout << "a = left side" << endl;
	cout <<	"d = right side" << endl; 
	cout << endl;
	cout << "Do not run the snake into the wall nor his own tail or you die" << endl;
	
	system("pause");
	Setup();
	while (!gameOver)
	{
	  Draw();
	  Input();
	  Logic();
	  
	  
	}
	return 0;


}

[shadder]

	switch (dir)
	{
	case LEFT:
		x--;
		break;
	case RIGHT:
		x++;
		break;
	case UP:
		y--;
		break;
	case DOWN:
		y++;
		break;

This is where I believe you should tweak the code to get your desired output, the rest is left for you....

PS: I can't compile the game on my PC so I can appreciate the code only, not the game

[LazyShadows]

can you please tell me on how to make the snake faster after it reaches the level using the code i've provided ... thank you

[shadder]

Like I said I can't compile the code on my PC, So all I can do is guess

when the level of the player increases increase the counter like x+=2/x+=3 so on....