// Example 105 from page 79

//

import java.util.Random;

class Example105 {

public static void main(String[] args) {

if (args.length != 1)

System.out.println("Usage: java Example105 <length>\n");

else {

System.out.println("Timing character replacement in a string:");

Random rnd = new Random();

int length = Integer.parseInt(args[0]);

char[] cbuf = new char[length];

for (int i=0; i<length; i++)

cbuf[i] = (char)(65 + rnd.nextInt(26));

String s = new String(cbuf);

for (int i=0; i<10; i++) {

Timer t = new Timer();

String res = replaceCharString(s, 'A', "HA");

System.out.print(t.check() + " ");

}

System.out.println();

}

}

static String replaceCharString(String s, char c1, String s2) {

StringBuilder res = new StringBuilder();

for (int i=0; i<s.length(); i++)

if (s.charAt(i) == c1)

res.append(s2);

else

res.append(s.charAt(i));

return res.toString();

}

// Simple timer, measuring wall-clock (elapsed) time in seconds

private final static class Timer {

private long start;

public Timer() {

start = System.nanoTime();

}

public double check() {

return (System.nanoTime() - start) / 1e9;

}

}

}