like i want to draw a polygon in c++ using graphics.h . then ask for coordinates and sides. x1, x2 ,y1 ,y2. then draw the polygon and show its area and perimeter as output. using their mathamatical formulas.
I have done this.
#include <iostream.h>
#include <graphics.h>
#include <conio.h>
#include <math.h>
void show_screen( );
void Polygon(const int,const int []);
void Line(const int,const int,const int,const int);
int main( )
{
int driver=VGA;
int mode=VGAHI;
int n=0;
do
{
show_screen( );
gotoxy(12,13);
cout<<"Enter the number of points : ";
cin>>n;
int *coordinates=new int[(n*2)];
for(int count=0;count<n;count++)>
{
gotoxy(8,18);
cout<<"Coordinates of Point-"<<(count+1)<<" (x"<<(count+1)<<",y"<<(count+1)<<") :";
gotoxy(12,21);
cout<<"Enter the value of x"<<(count+1)<<" = ";
cin>>coordinates[(count*2)];
gotoxy(12,22);
cout<<"Enter the value of y"<<(count+1)<<" = ";
cin>>coordinates[((count*2)+1)];
gotoxy(8,18);
cout<<" ";
gotoxy(12,21);
cout<<" ";
gotoxy(12,22);
cout<<" ";
}
initgraph(&driver,&mode,"c:\\tc\\Bgi");
setcolor(15);
Polygon(n,coordinates);
delete coordinates;
setcolor(15);
outtextxy(110,460,"Press <enter> to continue or any other key to exit.");
int key=int(getch( ));
if(key!=13)
break;
}
while(1);
return 0;
}
void Polygon(const int n,const int coordinates[])
{
if(n>=2)
{
Line(coordinates[0],coordinates[1],
coordinates[2],coordinates[3]);
for(int count=1;count<(n-1);count++)
Line(coordinates[(count*2)],coordinates[((count*2)+1)],
coordinates[((count+1)*2)],
coordinates[(((count+1)*2)+1)]);
}
}
void Line(const int x_1,const int y_1,const int x_2,const int y_2)
{
int color=getcolor( );
int x1=x_1;
int y1=y_1;
int x2=x_2;
int y2=y_2;
if(x_1>x_2)
{
x1=x_2;
y1=y_2;
x2=x_1;
y2=y_1;
}
int dx=abs(x2-x1);
int dy=abs(y2-y1);
int inc_dec=((y2>=y1)?1:-1);
if(dx>dy)
{
int two_dy=(2*dy);
int two_dy_dx=(2*(dy-dx));
int p=((2*dy)-dx);
int x=x1;
int y=y1;
putpixel(x,y,color);
while(x<x2)>
{
x++;
if(p<0)
p+=two_dy;
else
{
y+=inc_dec;
p+=two_dy_dx;
}
putpixel(x,y,color);
}
}
else
{
int two_dx=(2*dx);
int two_dx_dy=(2*(dx-dy));
int p=((2*dx)-dy);
int x=x1;
int y=y1;
putpixel(x,y,color);
while(y!=y2)
{
y+=inc_dec;
if(p<0)
p+=two_dx;
else
{
x++;
p+=two_dx_dy;
}
putpixel(x,y,color);
}
}
}
void show_screen( )
{
restorecrtmode( );
textmode(C4350);
textbackground(1);
cprintf(" Polygon ");
textbackground(8);
gotoxy(1,2);
}