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package ds1.student.orderofgrowth;
import stdlib.StdOut;
import stdlib.Stopwatch;
public class PerformanceOfStrings {
/** 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 makeStringUsingBuilder (int N) {
StringBuilder result = new StringBuilder ();
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 = makeStringUsingBuilder(N);
return sw.elapsedTime();
}
}
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