Java Program to Draw a Line using GUI

This is a Java Program to Draw a Line Using GUI

Problem Description

We have to write a program in Java such that it creates a line with random co-ordinates in an applet.

Expected Input and Output

For drawing a line, we can have the following set of input and output.

To Draw a Line :

On every execution of the program, 
it is expected that a line with random co-ordinates is drawn.

Problem Solution

1. Create a class and inherit the Applet class.
2. Generate four random integers x1, y1, x2, and y2 which lie within the bounds of the frame.
3. Draw a line from (x1,y1) to (x2,y2).

Program/Source Code

Here is source code of the Java Program to draw a line. The program is successfully compiled and tested using javac compiler on Fedora 30. The program output is also shown below.

/* Java Program to Draw a Line using GUI */

```
import java.applet.*;
```
```
import java.awt.*;
```
```
import java.lang.Math;
```
```
public class Line extends Applet
```
```
{
```
```
    //Function to initialize the applet
```
```
    public void init()
```
```
    {
```
```
	setBackground(Color.white);
```
```
    }
```
```
    //Function to draw the line
```
```
    public void paint(Graphics g)
```
```
    {
```

	int x1 = (int)(Math.random()*1000)%500;

	int y1 = (int)(Math.random()*1000)%500;

```
 
```

	int x2 = (int)(Math.random()*1000)%500;

	int y2 = (int)(Math.random()*1000)%500;

```
 
```
```
	g.drawLine(x1,y1,x2,y2);
```
```
    }
```
```
}
```
```
/*
```

<applet code = Line.class width = 500 height = 500>

```
</applet>
```
```
*/
```

To compile and execute the program use the following commands :

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>>> javac Line.java
>>> appletviewer Line.java

Program Explanation

1. The method Math.random of the Math class generates a random number between 0 and 1.
2. The method drawLine(x1,y1,x2,y2) of the Graphics class is used to draw a line from (x1,y1) to (x2,y2).

Runtime Test Cases

Here’s the run time test cases to draw a line for different input cases.

Test case 1 – To View a Line.