Write a Java program that reads a file and displays the file on the screen with a line number before each line

Java program that reads a file and displays the file on the screen with a line number before each line

Aim:

To write a Java program that reads a file and displays the file on the screen with a line number before each line.

Algorithm:

  1. import java package
  2. Create class Linenum
  3. Create main function
  4. public static void main( String[] args)throws IOException
    1. FileInputStream fil;
    2. LineNumberInputStream line;
    3. int i;
  5. Create try block
    1. fil = new FileInputStream(args[0]);
    2. line = new LineNumberInputStream( file );
  6. Catch( FileNotFoundException e )
  7. Print No such file found
  8. Inside do
  9. read line i = line.read();
  10. Use if condition
    1. if( i == ‘n’)
      1. System.out.print(line.getLineNumber()+” “);
    2. Else: System.out.print((char)i);
  11. Use while loop:
    1. while(i!=-1);
      1. fil.close();
      2. line.close();

Source Code:

import java.io.*;
class linenum
{
public static void main(String[] args)throws IOException
{
FileInputStream fil;
LineNumberInputStream line;
int i;
try
{
fil=new FileInputStream(args[0]);
line=new LineNumberInputStream(fil);
}
catch(FileNotFoundException e)
{
System.out.println("No such file found");
return;
}
do
{
i=line.read();
if(i=='n')
{
System.out.println();
System.out.print(line.getLineNumber()+" ");
}
else
System.out.print((char)i);
}while(i!=-1);
fil.close();
line.close();
}
}

Input:

This is file as input:
Demo.java
class Demo
 {
public static void main(java Demo beta gamma delta)
 {
 int n = 1 ;
 System.out.println(“The word is ” + args[ n ] );
 }
 }

Output:

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