RegEx2.java

/*
    RegEx2.java
    David Klick
    3/30/05

Demonstrates regular expression use interactively.
    Requires 2cities.txt file as input.
*/

import java.util.regex.*;
import java.io.*;

public class RegEx2 {
    public static void main(String[] args) throws IOException {
        String line, pat;
        BufferedReader kbd = new BufferedReader(
            new InputStreamReader(System.in));
        System.out.print("Enter a pattern (<Enter> to quit): ");
        pat = kbd.readLine();
        while (pat.length() > 0) {
            int matches = 0;
            BufferedReader in = new BufferedReader(
                new FileReader("2cities.txt"));
            line = in.readLine();
            while (line != null) {
                if (line.matches(pat)) {
                    if (matches++ == 0) System.out.println("Matches for " + pat + ": ");
                    System.out.printf("%5d: %s\n", matches, line);
                }
                line = in.readLine();
            }
            in.close();
            if (matches == 0) System.out.println("No matches found!");
            System.out.print("Enter a pattern (<Enter> to quit): ");
            pat = kbd.readLine();
        }
    }
}