REFLECTION OF A TRIANGLE (COMPUTER GRAPHICS)

#include<stdio.h>
#include<conio.h>
#include<graphics.h>
#include<stdlib.h>
void main()
{
int gd=DETECT,gm;
int x1,y1,x2,y2,x3,y3;
char a;
clrscr();
initgraph(&gd,&gm,"");
printf("\n enter the coordinates of triangle");
sacnf("%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3);
line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x1,y1);
line(320,0,320,430);
line(0,240,640,240);
printf("\n enter the axis of reflection");
scanf("%d",&a);
if(a='x'||a='X')
{
x1=x1;
x2=x2;
x3=x3;
y1=y1+240;
y2=y2+240;
y3=y3+240;
}
else
if(a='y'||a='Y')
{
y1=y1;
y2=y2;
y3=y3;
x1+=320;
x2+=320;
x3+=320;
}
printf("\n triangle after reflection");
line(x1,y1,x2,y2);
line(x2,y2,x3,y3);
line(x3,y3,x1,y1);
getch();
closegraph();
}