Revision of millions.java

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3 files changed, 110 insertions

millions.java(檔案已創建)

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1	+	import java.time.Duration;
2	+	import java.time.Instant;
3	+	import java.util.ArrayList;
4	+
5	+	public class Millions {
6	+
7	+
8	+	private Integer[] aArray;
9	+	private ArrayList<Integer> aList;
10	+
11	+	public Millions(Integer limit) {
12	+	aArray = new Integer[limit];
13	+	aList = new ArrayList<Integer>();
14	+	System.out.printf("Limit is %,d\n", limit);
15	+	}
16	+
17	+	public void printDuration(String msg, Instant start, Instant finish) {
18	+	long timeElapsed = Duration.between(start, finish).toMillis();
19	+	System.out.printf("%s: Elapsed time (ms): %s (secs): %s \n", msg, String.valueOf(timeElapsed),
20	+	String.valueOf(timeElapsed/1000));
21	+	}
22	+
23	+	public void loops(Integer limit) {
24	+	Instant start;
25	+	Instant finish;
26	+	Integer tempInt = 0;
27	+
28	+	start = Instant.now();
29	+	for (int i = 0; i < limit; i++) {
30	+	aArray[i] = i;
31	+	}
32	+	finish = Instant.now();
33	+	printDuration("Array Set", start, finish);
34	+
35	+	start = Instant.now();
36	+	for (int i = 0; i < limit; i++) {
37	+	tempInt = aArray[i];
38	+	tempInt = i;
39	+	}
40	+	finish = Instant.now();
41	+	printDuration("Array Get", start, finish);
42	+
43	+	start = Instant.now();
44	+	for (int i = 0; i < limit; i++) {
45	+	aList.add(i);
46	+	}
47	+	finish = Instant.now();
48	+	printDuration("ArrayList Set", start, finish);
49	+
50	+	start = Instant.now();
51	+	for (int i = 0; i < limit; i++) {
52	+	tempInt = aList.get(i);
53	+	tempInt = i;
54	+	}
55	+	finish = Instant.now();
56	+	printDuration("ArrayList Get", start, finish);
57	+	}
58	+	}

millions.md(檔案已創建)

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1	+	# Millions
2	+
3	+	run some loops in the millions arrays vs. arraylists
4	+
5	+	Sometimes, you just gotta mess about with code.
6	+	As in run experiments.
7	+	To see how things work, and to realize that 1 million is really a small number in a modern computer.
8	+
9	+	So, look at these examples, and maybe gen a project which copies this code and then run it an see what happens.
10	+
11	+	### And then, PLAY with it.
12	+
13	+
14	+

millionstext.java(檔案已創建)

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1	+	import static org.junit.Assert.*;
2	+
3	+	public class MillionsTest {
4	+
5	+	@org.junit.Test
6	+	public void loops() {
7	+	Integer upperlimit = 1000000;
8	+	Millions m = new Millions(upperlimit);
9	+
10	+	m.loops(upperlimit);
11	+
12	+	upperlimit = 5000000;
13	+	m = new Millions(upperlimit);
14	+
15	+	m.loops(upperlimit);
16	+
17	+	upperlimit = 10000000;
18	+	m = new Millions(upperlimit);
19	+
20	+	m.loops(upperlimit);
21	+
22	+	upperlimit = 20000000;
23	+	m = new Millions(upperlimit);
24	+
25	+	m.loops(upperlimit);
26	+
27	+	upperlimit = 50000000;
28	+	m = new Millions(upperlimit);
29	+
30	+	m.loops(upperlimit);
31	+
32	+	upperlimit = 70000000;
33	+	m = new Millions(upperlimit);
34	+
35	+	m.loops(upperlimit);
36	+
37	+	}
38	+	}