import java.io.Console;

import java.util.regex.Pattern;

import java.util.regex.Matcher;

// This demo comes from <a href="https://docs.oracle.com/javase/tutorial/essential/regex/test_harness.html">Java Tutorial</a>

public class RegexTestHarness{

public static void main(String[] args){

Console console = System.console();

if(console==null){

System.err.println("No console.");

System.exit(1);

}

while(true){

Pattern pattern = Pattern.compile(console.readLine("%nEnter your regex: "));

Matcher matcher = pattern.matcher(console.readLine("Enter input string to search: "));

boolean found = false;

while(matcher.find()){

console.format("I found the text \"%s\" starting at index %d and ending at index %d.%n",

matcher.group(), matcher.start(), matcher.end());

found = true;

}

if(!found){

console.format("No match found.%n");

}

}

}

}