# Java Program to Find Line Passing Through 2 Points

In the previous article, we have seen Java Program to Check if Three Points are Collinear

In this article we will discuss about how to find line passing through 2 pointsÂ  using Java programming language.

## Java Program to Find Line Passing Through 2 Points

Before jumping into the program directly, let’s first know how we can find line passing through 2 points.

Explanation:

Lets assume we have two point (x1,y1) and (x2,y2) .now we can find equation of the line by

x1x + y1y = c1

x2x + y2y = c2

Let’s see different ways to find line passing through 2 points.

### Method-1: Java Program to Find Line Passing Through 2 Points By Using Static Value

Approach :

• Initialize and declare the point x1,x2.
• Find out the equation of the line
• Print it .

Program :

class Main
{

// Driver method
public static void main(String args[])
{
IntsPoint x1 = new IntsPoint(3, 2);
IntsPoint x2 = new IntsPoint(2, 6);
lines_pts(x1,x2);
}

static class IntsPoint
{
int a,b;
public IntsPoint(int a, int b)
{
this.a = a;
this.b = b;
}
}
//find the line passing through 2 points by using equation
static void lines_pts(IntsPoint x1, IntsPoint x2)
{
int x = x2.b - x1.b;
int y = x1.a - x2.a;
int z = x * (x1.a) + y * (x1.b);
if (y < 0)
System.out.println("The line passing through points x1 and x2 is: " + x + "x - " + y + "y = " + z);
else
System.out.println("The line passing through points x1 and x2 is: " + x + "x + " + y + "y = " + z);
}
}

Output:

The line passing through points x1 and x2 is: 4x + 1y = 14

### Method-2: Java Program to Find Line Passing Through 2 Points By Using Dynamic Value

Approach :

• Take input of point x1,x2.
• Find out the equation of the line
• Print it .

Program :

import java.util.*;
class Main
{
// Driver method
public static void main(String args[])
{
Scanner s = new Scanner(System.in);
int l ,m ;
//taking input of point values
System.out.println("Enter values of point 1: ");
l=s.nextInt();
m=s.nextInt();
IntsPoint x1 = new IntsPoint(l, m);
System.out.println("Enter values of point 2: ");
l=s.nextInt();
m=s.nextInt();
IntsPoint x2 = new IntsPoint(l, m);
lines_pts(x1,x2);
}
static class IntsPoint
{
int a,b;
public IntsPoint(int a, int b)
{
this.a = a;
this.b = b;
}
}

//find the line passing through 2 points by using equation
static void lines_pts(IntsPoint x1, IntsPoint x2)
{
int x = x2.b - x1.b;
int y = x1.a - x2.a;
int z = x * (x1.a) + y * (x1.b);
if (y < 0)
System.out.println("The line passing through points x1 and x2 is: " + x + "x - " + y + "y = " + z);
else
System.out.println("The line passing through points x1 and x2 is: " + x + "x + " + y + "y = " + z);
}
}

Output:

Enter values of point 1:
3
2
Enter values of point 2:
2
4
The line passing through points x1 and x2 is: 2x + 1y = 8

Guys who are serious about learning the concepts of the java programming language should practice this list of programs in java and get a good grip on it for better results in exams or interviews.

Related Java Programs: