怎么填充国际象棋的背景色和方块色

#include<graphics.h>
#include<conio.h>
void main()
{
initgraph(400,450);
RECT r = {0, 0, 400, 450};
drawtext(_T("楚河 汉界"), &r, DT_CENTER | DT_VCENTER | DT_SINGLELINE);
for(int y=0;y<=450;y+=50)
{
if(y/10%2==1)
setcolor(RGB(255,0,0));
line(0,y,400,y);
}
for(int x=0;x<=400;x+=50)
{
if(x/10%2==1)
setcolor(RGB(255,0,0));
line(x,0,x,200);
}
for(int z=0;z<=450;z+=50)
{
if(x/10%2==1)
setcolor(RGB(255,0,0));
line(z,250,z,450);
}
line(150,0,250,100);
line(250,0,150,100);
line(150,450,250,350);
line(250,450,150,350);
getch();
closegraph();
}