Problem Description

Write a Java program to validate an IP Address using Regular Expressions.

Code

IPValidation.java

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Scanner;

public class IPValidation {
    public static void main(String[] args) {
        String ip = "192.168.0.1";
        String zeroTo255 = "(\\d{1,2}|(0|1)\\d{2}|2[0-4]\\d|25[0-5])";
        String regex = zeroTo255 + "\\." + zeroTo255 + "\\." + zeroTo255 + "\\." + zeroTo255;

        Pattern p = Pattern.compile(regex);
        Matcher m = p.matcher(ip);

        if (m.matches())
            System.out.println(ip + " is a valid IP address.");
        else
            System.out.println(ip + " is not a valid IP address.");
    }
}

Output

192.168.0.1 is a valid IP address.

Explanation

Regex: Pattern to match numbers from 0 to 255.
Matcher: Checks if the IP string matches the pattern.

Java Program to Validate IP Address

Problem Description

Code

Output

Explanation

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