вылезает ошибка. drawing operation was attempted when there was no current window dev c++

#include <conio.h>
#include <stdio.h>
#include <graphics.h>
#include <ctime>
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <iostream>
using namespace std;
void ship (int x, int y, int color1)
{
    setcolor(7);        
    line(x+20,y+70,x+20,y+90);
    line(x+20,y+90,x+90,y+90);
    line(x+90,y+90,x+120,y+70);
    line(x+20,y+70,x+120,y+70);
    line(x+60,y+70,x+60,y+20);
    line(x+30,y+30,x+90,y+30);
    line(x+30,y+30,x+30,y+60);
    line(x+30,y+60,x+90,y+60);
    line(x+90,y+30,x+90,y+60);
    setfillstyle (1,4);     
    bar(x+30,y+30,x+90,y+60);
    setfillstyle(1,7);
    bar(x+20,y+70,x+90,y+90);
    setfillstyle(1,7);
    setfillstyle(1,7);
    floodfill(x+100,y+75,7);
    line(x+90,y+70,x+120,y+70);
    line(x+90,y+90,x+120,y+70);
    line(x+90,y+70,x+90,y+90);
    _getch();
    closegraph();
}

void num()
{
    int x, y,dor; 
    initwindow(800, 800); 
    setfillstyle(1, 11);    
    bar(0, 0, 799, 799);
    x = 400; y = 400;   
   while (1) 
   {          
    ship ( x, y, 7); 
    
    int dor = getch(); 
    if ( _getch()==27 ) break; 
    ship(x,y,11); 
    switch ( dor ) 
    {
        case 100:  x --; break;
        case 102:  x ++; break; 
        case 104:  y --; break;
        case 98:  y ++; 
        
    }
    
    }
    _getch();  
    closegraph();
}
int main()
{
    setlocale(LC_ALL, "Russian");
    cout << "Ñâîáîäíîå äâèæåíèå îáúåêòà - ââåäèòå 1" << endl;
    cout << "Äâèæåíèå îáúåêòà ñ ïîìîùüþ êëàâèàòóðû - ââåäèòå 2" << endl;
    cout << "Âûõîä èç ïðîãðàììû - ââåäèòå 3" << endl;
    int c;
    cin >> c;
    switch (c)
    {
        case 1:
        move(c);
            break;
        case 2:
            num();
            break;
        default:
            exit(0);
    }
    
}