#include?
#include?
#include??
void?cb_line（int?x1int?y1int?x2int?y2）
{
?????int?dxdynkif;
?????int?xy;
?????dx=abs（x2-x1）;
?????dy=abs（y2-y1）;
?????n=dx+dy;
?????if（x2>=x1）
?????{k=y2>=y1??1:4;x=x1;y=y1;}
?????else
?????{k=y2>=y1??2:3;x=x1;y=y1;}
?????putpixel（xy1）;
?????for（i=0f=0;i????????if（f>0）
????????????switch（k）{
??????????????????????case?1:putpixel（x++y1）;f-=dy;break;
??????????????????????case?2:putpixel（xy++1）;f-=dx;break;