package algs14;
import stdlib.*;
public class XPerformanceOfStrings {
  /** create a string consisting of N asterisks */
  public static String makeStringUsingConcat (int N) {
    String result = "";
    for (int i=0; i<N; i+=1) {
      result = result + "*";
      ops += result.length();
    }
    return result;
  }
  /** create a string consisting of N asterisks */
  public static String makeStringUsingBuffer (int N) {
    StringBuffer result = new StringBuffer ();
    for (int i=0; i<N; i+=1) { 
      result.append ("*");
      ops += 1;
    }
    return result.toString ();
  }
  private static long ops;
  private static String result;
  public static void main(String[] args) {
    timeTrial(32);
    StdOut.println(result);
    
    int MIN = 256; 
    int MAX = 1_000_000_000;
    double prevTime = timeTrial(MIN);
    double prevOps = ops;
    for (int N = MIN*2; N<=MAX; N += N) {
      double time = timeTrial(N);
      StdOut.format ("Elapsed count f(%,13d): %,17d: %10.3f [%10.3f : %10.3f]\n", N, ops, ops / prevOps, time, time/prevTime);
      prevTime = time;
      prevOps = ops;
    }
  }
  public static double timeTrial(int N) {
    ops = 0;
    Stopwatch sw = new Stopwatch();
    result = makeStringUsingConcat(N);
    //result = makeStringUsingBuffer(N);    
    return sw.elapsedTime();
  }
}