WAP to Replace Last Two Special Character With Dots

Replace Last Two Special Character With Dots: This Java program aims to remove the last alphanumeric character from a given input string and replace it with dots.

Replace Last Two Special Character With Dots

package com.softwaretestingo.interviewprograms;
public class InterviewPrograms40 
{
	/*
	 * Input string : Aut@oma#tion@# 
	 * Output: Aut@oma#tion.. 
	 * Input maybe any string, but only the last alphanumeric character should be removed
	 */
	public static void main(String[] args) 
	{
		String s = "Aut@oma#tion@#";
		String [ ] newstring = s.split("");
		int count = 0 ;
		String last = "";
		for ( int i = s.length()-1; i>=0;i--)
		{
			if (!newstring[i].matches("[a-zA-Z]"))
			{
				count++;
				last=last+".";
			}
			else
			{
				break;
			}
		}
		System.out.print(s.substring(0, s.length()-count)+last);	
	}
}

Output

Aut@oma#tion..

Here’s a breakdown of the program:

1. Define the main method:
   • The entry point of the program is the main method.
2. Initialize the input string and split it into an array of characters:
   • The string s is initialized with the value “Aut@oma#tion@#”.
   • The split(“”) method is used to convert the input string into an array of characters named newstring.
3. Find the last non-alphanumeric character:
   • A variable count is initialized to zero to keep track of the number of non-alphanumeric characters at the end of the string.
   • A variable last is initialized as an empty string to store the dots that will replace the removed characters.
   • The program iterates through the characters in reverse order (from the end of the string to the beginning).
   • If a character is not a letter (uppercase or lowercase) using the regex [a-zA-Z], it means it is non-alphanumeric.
   • If the character is non-alphanumeric, the count is incremented, and a dot is appended to the last string.
   • If a letter is encountered, the loop breaks since we have reached the last alphanumeric character.
4. Build the output string:
   • The program constructs the output string by removing the last count characters from the original string s and appending the last string (dots) at the end.
5. Print the output:
   • The program prints the final s string, which has the last alphanumeric character replaced with dots.

For the given input “Aut@oma#tion@#”, the program removes the last alphanumeric character “n” and replaces it with dots, resulting in “Aut@oma#tion..”.