lines are intersecting or notin cg with eg.

Determine whether lines are intersecting or not.

#include<iostream.h>

#include<conio.h>

#include<math.h>

#include<graphics.h>

void main()

{

clrscr();

int x1,x2,y1,y2,x3,x4,y3,y4;

int gd=DETECT,gm;

initgraph(&gd,&gm,"d:\\turboc3");

cout<<"Enter the co-ordinates of 1st line:";

cout<<"\n\nCo-ordinates of Initial points:";

cout<<"\nx-axis:";

cin>>x1;

cout<<"y-axis:";

cin>>y1;

cout<<"Enter the co-ordinates of End points:";

cout<<"\nx-axis:";

cin>>x2;

cout<<"y-axis:";

cin>>y2;

cout<<"\n\nEnter the co-ordinates of 2nd line:";

cout<<"\n\nCo-ordinates of Initial points:";

cout<<"\nx-axis:";

cin>>x3;

cout<<"y-axis:";

cin>>y3;

cout<<"Enter the co-ordinates of End points:";

cout<<"\nx-axis:";

cin>>x4;

cout<<"y-axis:";

cin>>y4;

line(x1,y1,x2,y2);

line(x3,y3,x4,y4);

if((x3<x1)&&(x4>x2)&&(y3<y1)&&(y4>y2))

{

cout<<"Lines are intersecting:" ;

}

else

{

cout<<"lines are not intersecting:";

}

getch();

}

Output:

Case 1: lines are Intersecting:

Enter the co-ordinates of 1st line:

Co-ordinates of Initial points:

x-axis:100

y-axis:150

Enter the co-ordinates of End points:

x-axis:600

y-axis:175

Enter the co-ordinates of 2nd line:

Co-ordinates of Initial points:

x-axis:50

y-axis:125

Enter the co-ordinates of End points:

x-axis:700

y-axis:200

2: lines are not Intersecting:

Enter the co-ordinates of 1st line:

Co-ordinates of Initial points:

x-axis:100

y-axis:200

Enter the co-ordinates of End points:

x-axis:200

y-axis:250

Enter the co-ordinates of 2nd line:

Co-ordinates of Initial points:

x-axis:120

y-axis:230

Enter the co-ordinates of End points:

x-axis:220

y-axis:280