My do while loop is not entering the while loop - do-while

I'm trying to complete my homework assignment and am having trouble. The instructions state that I need to change the while expression to a not but whenever I do it wont enter the loop.
import java.util.Scanner;
public class GuessNumberApp {
public static void main(String[] args) {
final int LIMIT = 10;
System.out.println("Guess the number!");
System.out.println("I'm thinking of a number from 1 to " + LIMIT);
System.out.println();
// get a random number between 1 and the limit
double d = Math.random() * LIMIT; // d is >= 0.0 and < limit
int number = (int) d; // convert double to int
number++; // int is >= 1 and <= limit
Scanner sc = new Scanner(System.in);
int count = 1;
int guess;
do {
System.out.print("Your guess: ");
guess = Integer.parseInt(sc.nextLine());
}
while (guess != number); {
if (guess < 1 || guess > LIMIT) {
System.out.println("Invalid guess. Try again.");
}
else if (guess < number) {
System.out.println("Too low.");
count++;
}
else if (guess > number) {
System.out.println("Too high.");
count++;
}
}
System.out.println("You guessed it in " + count + " tries.\n");
System.out.println("Bye!");
}
}

Related

MQL4 automatic stop

My Martingale EA should be stopped automatically if the previously manually set limit has been reached or exceeded. The last trade should expire normally and not be interrupted.
So far, I've tried the following code, without interruption, etc. the code works fine.
I also heard about RemoveExpert, but I do not know how to do it. Am grateful for any help :)
enum tradeD{Buy=1, Sell=2};
input tradeD TradeType = Buy;
input double Initial_Lot = 0.01;
input double Lot_Factor = 2;
input int Max_Spread = 30;
input double Pct_SL = 0.1; // Percentage Stop Loss
input double Pct_TP = 0.1; // Percentage Take Profit
input int Magic_Number= 73726;
input int interrupt = 1,0000;
input bool StopEA = false;
int OnInit()
{
return(INIT_SUCCEEDED);
}
void OnDeinit(const int reason)
{
}
int start()
{
if (StopEA == true) { return(0); } //This line will skip the execution of EA.
}
void OnTick()
{
if(OpenOrders()==0 && (SymbolInfoInteger(Symbol(),SYMBOL_SPREAD)<Max_Spread||Max_Spread==0)){
if(TradeType==Buy){
double flot=Initial_Lot;
double etp=Ask+(Ask*(Pct_TP/100));
etp=NormalizeDouble(etp,Digits);
double esl=Ask-(Ask*(Pct_TP/100));
esl=NormalizeDouble(esl,Digits);
if (ask <= interrupt) { StopEA = true; return(0); }
if(lastProfit()<0){
flot=NormalizeDouble(lastLot()*Lot_Factor,2);
}
int snd=OrderSend(Symbol(),OP_BUY,flot,Ask,10,esl,etp,NULL,Magic_Number,0,clrAliceBlue);
}
if(TradeType==Sell){
double flot=Initial_Lot;
double etp=Bid-(Bid*(Pct_TP/100));
etp=NormalizeDouble(etp,Digits);
double esl=Bid+(Bid*(Pct_TP/100));
esl=NormalizeDouble(esl,Digits);
if (bid >= interrupt) { StopEA = true; return(0); }
if(lastProfit()<0){
flot=NormalizeDouble(lastLot()*Lot_Factor,2);
}
int snd=OrderSend(Symbol(),OP_SELL,flot,Bid,10,esl,etp,NULL,Magic_Number,0,clrAliceBlue);
}
}
//checkProfit();
}
int checkProfit(){
int total=0;
for(int i=OrdersTotal()+5; i >= 0; i--)
{
if(OrderSelect(i,SELECT_BY_POS,MODE_TRADES)){
string ordsymB = OrderSymbol();
int ordtypeB =OrderType();
int magicnB = OrderMagicNumber();
int magicn=magicnB;
double ordProfit=OrderProfit();
int tick=OrderTicket();
double oLots=OrderLots();
if(ordsymB==Symbol() && magicnB==Magic_Number){
double pctBalT=AccountBalance()*(Pct_TP/100);
double pctBalS=AccountBalance()*(Pct_SL/100);
if(ordProfit>=pctBalT){
int clo=OrderClose(tick,oLots,Close[0],10,clrAntiqueWhite);
}
if(ordProfit<0 && MathAbs(ordProfit)>=pctBalS){
int clo=OrderClose(tick,oLots,Close[0],10,clrAntiqueWhite);
}
}
}
}
return (total);
}
int OpenOrders(){
int total=0;
for(int i=OrdersTotal()+5; i >= 0; i--)
{
if(OrderSelect(i,SELECT_BY_POS,MODE_TRADES)){
string ordsymB = OrderSymbol();
int ordtypeB =OrderType();
int magicnB = OrderMagicNumber();
int magicn=magicnB;
if(ordsymB==Symbol() && magicnB==Magic_Number){
total++;
}
}
}
return (total);
}
double lastProfit(){
double total=0;
datetime lastTime=0;
for(int i=OrdersHistoryTotal(); i >= 0; i--)
{
if(OrderSelect(i,SELECT_BY_POS,MODE_HISTORY)){
string ordSym=OrderSymbol();
int ordType=OrderType();
datetime ordTime=OrderOpenTime();
double ordLot=OrderLots();
double ordOp=OrderOpenPrice();
int ordMag=OrderMagicNumber();
double ordProfit=OrderProfit();
if(ordSym==Symbol() && ordTime>lastTime && ordMag==Magic_Number){
lastTime=ordTime;
total=ordProfit;
}
}
}
return(total);
}
double lastLot(){
double total=0;
datetime lastTime=0;
for(int i=OrdersHistoryTotal(); i >= 0; i--)
{
if(OrderSelect(i,SELECT_BY_POS,MODE_HISTORY)){
string ordSym=OrderSymbol();
int ordType=OrderType();
datetime ordTime=OrderOpenTime();
double ordLot=OrderLots();
double ordOp=OrderOpenPrice();
int ordMag=OrderMagicNumber();
if(ordSym==Symbol() && ordTime>lastTime && ordMag==Magic_Number){
lastTime=ordTime;
total=ordLot;
}
}
}
return(total);
}
if(tick_counter>=ticks_to_close)
{
ExpertRemove();
Print(TimeCurrent(),": ",__FUNCTION__," expert advisor will be unloaded");
}

How to make Break even trigger more than one time in one entry

I now trying to make Break Even Code trigger more than one time,
example EA entry is 1.28000 and stop loss 1.28500
if current price reach 1.175000(50pips), sl move to break even such as to 1.28000(5pips).
EA will not make more modify order after condition are meet.
so how to trigger break even again if price reach 1.17000(100pips), sl move to (1.175000)(50 pips)
and again price reach 1.165000(150pips),sl move to 1.17000(100pips)
I want to make
BE_B_M(sl move to(example:5))
and
BE_B_T(price reach(example:50))
as variable and every time price reach target variable change to next value
so became
BE_B_M(sl move to(example:50)) and BE_B_T(price reach(example:100))
The entire code is as follows
extern double BE_T_1 = 50;
extern double BE_M_1 = 5;
extern double BE_T_2 = 100;
extern double BE_M_2 = 50;
extern double BE_T_3 = 150;
extern double BE_M_3 = 100;
double BE_S_M;
double BE_S_T;
void MOVE_BE_1()
{
for(int b=OrdersTotal()-1;b>=0;b--)
{
if(OrderSelect(b,SELECT_BY_POS,MODE_TRADES))
if(OrderMagicNumber()!=M_Number)continue;
if(OrderSymbol()==Symbol())
if(OrderType()==OP_BUY)
if(Bid-OrderOpenPrice()>BE_S_T*Pips)
if(OrderOpenPrice()>OrderStopLoss())
if(!OrderModify(OrderTicket(),OrderOpenPrice(),OrderOpenPrice()+(BE_S_M*Pips),OrderTakeProfit(),0,CLR_NONE))
Print("eror");
}
for(int s=OrdersTotal()-1;s>=0;s--)
{
if(OrderSelect(s,SELECT_BY_POS,MODE_TRADES))
if(OrderMagicNumber()!=M_Number)continue;
if(OrderSymbol()==Symbol())
if(OrderType()==OP_SELL)
if(OrderOpenPrice()-Ask>BE_S_T*Pips)
if(OrderOpenPrice()<OrderStopLoss())
if(!OrderModify(OrderTicket(),OrderOpenPrice(),OrderOpenPrice()-(BE_S_M*Pips),OrderTakeProfit(),0,CLR_NONE))
Print("eror");
}
}
i expect sl will move after price reach every 50pips from entry
Here you can put all the 3 break even levels on one function.
Note: you can use 1 for-loop for both OP_BUY and OP_SELL
Here is my OnInit()
// Global variable
double point;
int OnInit()
{
if(Digits == 5 || Digits == 3) point=Point*10;
else point=Point;
return(INIT_SUCCEEDED);
}
Here is the BreakEven() function
//+------------------------------------------------------------------+
//| Break even the trade at 3 levels |
//+------------------------------------------------------------------+
void BreakEven()
{
// get the stop level for that symbol
double stopLevel = SymbolInfoInteger(Symbol(),SYMBOL_TRADE_STOPS_LEVEL)*Point;
for(int i=OrdersTotal()-1;i>=0;i--)
{
if(!OrderSelect(i,SELECT_BY_POS,MODE_TRADES)) continue;
if(OrderMagicNumber()!=M_Number)continue;
if(OrderSymbol()!=Symbol())continue;
if(OrderType()==OP_BUY)
{
double profitPips=Bid-OrderOpenPrice();
double newSL=OrderStopLoss();
if(profitPips>=BE_T_1*point && OrderStopLoss()<OrderOpenPrice()) // Break Even
{
newSL=OrderOpenPrice()+BE_M_1*point;
}
else if(profitPips>=BE_T_3*point) // 150/100
{
newSL=OrderOpenPrice()+BE_M_3*point;
}
else if(profitPips>=BE_T_2*point) // 100/50
{
newSL=OrderOpenPrice()+BE_M_2*point;
}
if(newSL>=OrderStopLoss()+Point && newSL<Bid-stopLevel)
if(!OrderModify(OrderTicket(),OrderOpenPrice(),NormalizeDouble(newSL,Digits),OrderTakeProfit(),0))
Print("Error at BE: ",GetLastError());
}
else if(OrderType()==OP_SELL)
{
double profitPips=OrderOpenPrice()-Ask;
double newSL=OrderStopLoss();
if(profitPips>=BE_T_1*point && (OrderStopLoss()>OrderOpenPrice() || OrderStopLoss()==0)) // Break Even
{
newSL=OrderOpenPrice()-BE_M_1*point;
}
else if(profitPips>=BE_T_3*point) // 150/100
{
newSL=OrderOpenPrice()-BE_M_3*point;
}
else if(profitPips>=BE_T_2*point) // 100/50
{
newSL=OrderOpenPrice()-BE_M_2*point;
}
if(newSL<=OrderStopLoss()-Point && newSL>Ask+stopLevel)
if(!OrderModify(OrderTicket(),OrderOpenPrice(),NormalizeDouble(newSL,Digits),OrderTakeProfit(),0))
Print("Error at BE: ",GetLastError());
}
}
}
I didn't test this myself in a trade, but it should work.

Data From Arduino Yun To Google Spreadsheet

I am working on a project where I am sending a timestamp from and Arduino Yun to a Google Spreadsheet. I have a PIR Sensor connected to the Yun. When motion is detected I am sending the value to the spreadsheet. Currently the value is going into one column.
This is not ideal because I want to create a chart from the data so I want the time and date to be in two different columns. Like the sample below.
Arduino Sketch
#include <Bridge.h>
#include <Temboo.h>
#include "TembooAccount.h"
#include <Process.h>
int pir_pin = 8;
Process date;
int hours, minutes, seconds;
int lastSecond = -1;
const String GOOGLE_CLIENT_ID = "";
const String GOOGLE_CLIENT_SECRET = "";
const String GOOGLE_REFRESH_TOKEN = "";
const String SPREADSHEET_TITLE = "";
int numRuns = 1;
int maxRuns = 100;
void setup() {
Serial.begin(9600);
delay(4000);
pinMode(pir_pin, INPUT);
while (!Serial);
Serial.println("Time Check");
if (!date.running()) {
date.begin("date");
date.addParameter("+%T %D");
date.run();
}
Serial.print("Initializing the bridge... ");
Bridge.begin();
Serial.println("Done!\n");
}
void loop()
{
if (digitalRead(pir_pin) == true) {
if (!date.running()) {
date.begin("date");
date.addParameter("+%T %D");
date.run();
}
while (date.available() > 0) {
String timeString = date.readString();
int firstColon = timeString.indexOf(":");
int secondColon = timeString.lastIndexOf(":");
String hourString = timeString.substring(0, firstColon);
String minString = timeString.substring(firstColon + 1, secondColon);
String secString = timeString.substring(secondColon + 1);
hours = hourString.toInt();
minutes = minString.toInt();
lastSecond = seconds;
seconds = secString.toInt();
if (numRuns <= maxRuns) {
Serial.println("Running AppendRow - Run #" + String(numRuns++));
unsigned long now = millis();
Serial.println("Getting sensor value...");
Serial.println("Appending value to spreadsheet...");
TembooChoreo AppendRowChoreo;
AppendRowChoreo.begin();
AppendRowChoreo.setAccountName(TEMBOO_ACCOUNT);
AppendRowChoreo.setAppKeyName(TEMBOO_APP_KEY_NAME);
AppendRowChoreo.setAppKey(TEMBOO_APP_KEY);
AppendRowChoreo.setChoreo("/Library/Google/Spreadsheets/AppendRow");
AppendRowChoreo.addInput("ClientID", GOOGLE_CLIENT_ID);
AppendRowChoreo.addInput("ClientSecret", GOOGLE_CLIENT_SECRET);
AppendRowChoreo.addInput("RefreshToken", GOOGLE_REFRESH_TOKEN);
AppendRowChoreo.addInput("SpreadsheetTitle", SPREADSHEET_TITLE);
String rowData = timeString;
AppendRowChoreo.addInput("RowData", rowData);
unsigned int returnCode = AppendRowChoreo.run();
if (returnCode == 0) {
Serial.println("Success! Appended " + rowData);
Serial.println("");
} else {
while (AppendRowChoreo.available()) {
char c = AppendRowChoreo.read();
Serial.print(c);
}
}
AppendRowChoreo.close();
}
Serial.println("Waiting...");
delay(5000);
}
}
}
How would I alter the code to achieve the above.
I work for Temboo.
You can set multiple columns in the AppendRow Choreo by separating each value in rowData with a comma. For your case, you'd want your rowData to look like this: "19:35:26,4/22/2016". You could try something like timeString.replace(" ",",");.
Hopefully this helps. If you have any other questions, feel free to contact us at https://temboo.com/support

Linked list exercise in C, what is wrong?

The code below does compile, but it doesn't run as it should.
I'm not sure what am I doing wrong, so would someone be willing to tell me what I did wrong and what I should have done better.
What do I need to change to make it run properly?
#include<stdio.h>
#include<stdlib.h>
typedef struct sub_Node
{
int value;
struct sub_Node *next;
}sub_Node;
typedef struct Node
{
char *name;
struct Node *next;
struct sub_Node *sub_start;
}Node;
Node *start;
void add_player(char *name)
{
Node *temp;
temp = (Node *)malloc(sizeof(Node));
temp->next = start;
temp->name = name;
temp->sub_start = (sub_Node *)malloc(sizeof(sub_Node));
temp->sub_start->next = NULL;
temp->sub_start->value = -1;
start = temp;
}
void initialize()
{
char *p;
p = "\0";
add_player(p);
}
void remove_player(char *name)
{
Node *p;
for(p = start; p!= NULL; p = p->next)
if(p->name == name)
{
p->name = p->next->name;
p->next = p->next->next;
}
}
sub_Node* add_descending(sub_Node* sub_start, int piece_value)
{
sub_Node *temp, *prev, *next;
temp = (sub_Node *)malloc(sizeof(sub_Node));
temp->value = piece_value;
temp->next = NULL;
prev = NULL;
next = sub_start;
while(next && next->value >= piece_value)
{
prev = next;
next = next->next;
}
if(!next)
{
prev->next = temp;
}
else
{
if(prev)
{
temp->next = prev->next;
prev->next = temp;
}
else
{
temp->next = sub_start;
sub_start = temp;
}
}
return sub_start;
}
void add_piece(char *name, int piece_value)
{
Node *p;
int c;
for(p = start; p!=NULL; p = p->next)
if(p->name == name)
p->sub_start = add_descending(p->sub_start, piece_value);
}
void print_pieces(char *name)
{
Node *p;
sub_Node *q;
for(p = start; p!=NULL; p = p->next)
if(p->name == name)
{
printf("The values of the owned pieces are:");
for(q = p->sub_start; q->value != -1; q = q->next)
printf(" %d", q->value);
}
}
int lose_piece(char *name)
{
Node *p;
sub_Node *q;
int aux;
for(p = start; p!=NULL; p = p->next)
if(p->name == name)
{
for(q = p->sub_start; q->next->value != -1; q = q->next) {}
aux = q->value;
q->value = q->next->value;
q->next = q->next->next;
return aux;
}
}
void print_players()
{
Node *p;
printf("The players are: ");
for(p = start; p->name != "\0"; p = p->next)
printf("%s ", p->name);
printf("\n");
}
int main()
{
initialize();
int y, value;
char name[20];
printf("Insert a digit to execute the desired task:\n"
"<0> end the program\n"
"<1> add a player, who doesn't own any piece yet\n"
"<2> remove a player and all his pieces\n"
"<3> print the name of all the players\n"
"<4> a player gets a piece\n"
"<5> a player loses the piece with the lowest value out of the ones that he has\n"
"<6> prints the pieces of a player in a descending order by value\n\n");
do
{
printf("digit: ");
scanf("%d", &y);
switch(y)
{
case 1:
printf("Insert the player's name: ");
scanf("%s", name);
add_player(name);
break;
case 2:
printf("Insert the player's name: ");
scanf("%s", name);
remove_player(name);
break;
case 3:
print_players();
break;
case 4:
printf("Insert the player's name: ");
scanf("%s", name);
printf("Insert the value of the piece: ");
scanf("%d", value);
add_piece(name, value);
break;
case 5:
printf("Insert the player's name: ");
scanf("%s", name);
printf("\nThe player loses the piece: %d\n", lose_piece(name));
break;
case 6:
printf("Insert the player's name: ");
scanf("%s", name);
print_pieces(name);
}
} while(y != 0);
return 0;
}
your two main problems where this scanf("%d", value); value should be passed by reference like this scanf("%d", &value); and the second is string comparison in c as in your code p->name != "\0" and if(p->name == name) this is wrong because actually you are making comparison between addresses of strings (where it resides in memory) not strings values. to compare strings in c you have to use strcmp and families.
Actually 3 main problems. for setting string values as you did in temp->name = name; is little bit more complicated than that. because you are assigning to temp->name a string from the stack that is volatile (the stack will be more likely invalid soon you return from the function) . in your case you have to alloc a new string by using malloc (and friends) or just by using strdup.
here is as a bonus a slightly rewrite of your program, you will find many advises and is a good starting point for how to structure your code for an easy maintenance.
still want to advise you to change members and variables to more declarative names as in sub_start and sub_Node can be PieceNode and pieces respectively.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct sub_Node
{
int value;
struct sub_Node *next;
}sub_Node;
typedef struct Node
{
char *name;
struct Node *next;
struct Node *prev; // this to make life easyer
struct sub_Node *sub_start;
}Node;
Node *start = NULL;
Node *find_player(char *name){
Node *tmp = start;
while( tmp ){
if(strcmp(tmp->name,name) == 0 )
break;
tmp = tmp->next;
}
return tmp;
}
// int to return Error Code
//
int add_player(char *name)
{
Node *temp;
if( find_player(name)) {
printf("player %s already exists\n", name);
return 1;
}
// do not cast malloc
temp = malloc(sizeof(Node));
if( !temp ){
printf ("not enough memory\n");
return 2;
}
temp->name = strdup ( name); // here was your error
temp->sub_start = NULL; // keep it simple
temp->prev = NULL;
temp->next = start;
if(start)
start->prev = temp;
start = temp;
return 0; // no error
}
void DestroyPieces(sub_Node* piece){
if( piece ) {
DestroyPieces( piece->next );
free( piece );
}
}
// as usual use int to return error code
int remove_player(char *name)
{
Node *player = find_player(name);
if ( !player ){
return 1; // player not found
}
if ( player->next ){
player->next->prev = player->prev;
}
if ( player->prev ){
player->prev->next = player->next;
}
DestroyPieces(player->sub_start);
free(player->name);
free(player);
return 0; // success
}
sub_Node* new_piece(int value){
sub_Node *temp = malloc( sizeof(sub_Node) );
if(temp){
temp->value = value;
temp->next = NULL;
}
return temp;
}
// int to return error code
// pass sub_start as pointer to pointer, as it might be updated
int add_descending(sub_Node** psub_start, int piece_value)
{
sub_Node *piece, *current, *prev = NULL;
if( !psub_start){
return 5; // this should not happen
}
current = *psub_start;
piece = new_piece( piece_value );
if( !piece ) return 1; // no mem
if(!current){
// this is the first and only one
*psub_start = piece;
return 0; // OK
}
while(current && current->value >= piece_value)
{
prev = current;
current = current->next;
}
if( prev )
prev->next = piece;
piece->next = current;
if( current == *psub_start ){
*psub_start = piece;
}
return 0 ; // OK
}
void add_piece(Node * player, int piece_value)
{
if ( !player) {
return ;
}
if(add_descending (&(player->sub_start), piece_value) == 0 )
return ; //OK
printf("an error occured while adding a piece (%d) to player '%s'\n",piece_value,player->name);
}
void print_pieces(Node *player)
{
sub_Node *q;
if( !player ){
return;
}
if( !player->sub_start ){
printf("Player '%s' has no pieces\n",player->name);
return;
}
printf("The values of the owned pieces are:");
for(q = player->sub_start; q != NULL; q = q->next)
printf(" %d", q->value);
printf("\n");
}
void lose_piece(Node *player)
{
if( !player ){
return;
}
sub_Node *q, *prev = NULL;
int aux;
if( !player->sub_start ){
printf("Player '%s' has no pieces\n",player->name);
return;
}
// i think you want drop the last one
for(q = player->sub_start; q->next != NULL ;prev = q, q = q->next) {
;
}
if(prev)
prev->next = NULL;
else
player->sub_start = NULL;
aux = q->value;
free(q);
printf("\nThe player loses the piece: %d\n", aux);
return;
}
void print_players()
{
Node *p;
if( !start ){
printf("there are no players, try to add some\n");
return;
}
printf("The players are: ");
for(p = start; p != NULL; p = p->next)
printf("%s ", p->name);
printf("\n");
}
void print_menu(void){
printf("Insert a digit to execute the desired task:\n"
"<0> end the program\n"
"<1> add a player, who doesn't own any piece yet\n"
"<2> remove a player and all his pieces\n"
"<3> print the name of all the players\n"
"<4> a player gets a piece\n"
"<5> a player loses the piece with the lowest value out of the ones that he has\n"
"<6> prints the pieces of a player in a descending order by value\n\n");
}
Node * get_player(char *name){
Node *player = find_player(name);
if(!player)
printf("Player '%s' do not exists\n",name);
return player;
}
int main()
{
// initialize(); no more needed
int y, value;
char name[20];
Node *player;
print_menu();
do
{
printf("digit: ");
scanf("%d", &y);
switch(y)
{
case 1:
printf("Insert the player's name: ");
scanf("%s", name);
add_player(name);
break;
case 2:
printf("Insert the player's name: ");
scanf("%s", name);
player = get_player(name);
if( player )
break;
case 3:
print_players();
break;
case 4:
printf("Insert the player's name: ");
scanf("%s", name);
player = get_player(name);
if( player ){
printf("Insert the value of the piece: ");
scanf("%d", &value);
add_piece(player, value);
}
break;
case 5:
printf("Insert the player's name: ");
scanf("%s", name);
player = get_player(name);
lose_piece(player);
break;
case 6:
printf("Insert the player's name: ");
scanf("%s", name);
player = get_player(name);
print_pieces(player);
}
} while(y != 0);
return 0;
}

Why is this Dart code so slow compared to java's implementation?

The dart codes as follows is extremely slow compared to java's implementation.
//test.dart
import 'dart:io';
void main(){
for(int i = 0; i < 1 << 25;i++){
stdout.write(i); // or directly print(i);
}
stdout.close();
}
java version:
//Test.java
import java.io.*;
public class Test{
public static void main(String[]args)throws Exception {
try{
PrintWriter out = new PrintWriter(System.out);
for(int i = 0;i < 1 << 25; i++){
out.print(i);
}
out.close();
}catch(Exception e){}
}
}
$ time java Test > /dev/null
real 0m6.421s
user 0m0.046s
sys 0m0.031s
$ time dart Test.dart > /dev/null
real 0m51.978s
user 0m0.015s
sys 0m0.078s
Is stdout/print() unbuffered by default in Dart? Is there something like java's PrintWriter? thanks. (Update: after warming up vm, stdout is 2x slower than java )
real 0m15.497s
user 0m0.046s
sys 0m0.047s
===============================================================================
Update Sep 30, 2013
I have implemented custom buffers for both dart and java codes to make a further comparing,now the result is as follows:
//test.dart
final int SIZE = 8192;
final int NUM = 1 << 25;
void main(){
List<int> content = new List(SIZE);
content.fillRange(0, SIZE, 0);
for(int i = 0; i < NUM;i++){
if(i % SIZE == 0 && i > 0)
print(content);
content[i % SIZE] = i;
}
if (NUM % SIZE ==0)
print(content);
else
print(content.sublist(0, NUM % SIZE));
}
java version:
//Test.java
import java.util.Arrays;
public class Test{
public static final int SIZE = 8192;
public static final int NUM = 1 << 25;
public static void main(String[]args)throws Exception {
try{
int[] buf = new int[SIZE];
for(int i = 0;i < NUM; i++){
if(i % SIZE == 0 && i > 0)
System.out.print(Arrays.toString(buf));
buf[i % SIZE] = i;
}
if(NUM % SIZE == 0)
System.out.print(Arrays.toString(buf));
else
{
int[] newbuf = new int[NUM % SIZE];
newbuf = Arrays.copyOfRange(buf, 0, (NUM % SIZE));
System.out.print(Arrays.toString(newbuf));
}
}catch(Exception e){}
}
}
$ time java Test > /dev/null
real 0m7.397s
user 0m0.031s
sys 0m0.031s
$ time dart test.dart > /dev/null
real 0m22.406s
user 0m0.015s
sys 0m0.062s
As you see, dart is still 3x slower than java.
Maybe your code does not get optimized by the VM.
Only "frequenly" used functions are compiled and executed as native code.
Usually for such benchmark, you have to put the tested code into a function and perform a warmup. For exemple:
//test.dart
import 'dart:io';
void f(nb_shift) {
for(int i = 0; i < 1 << nb_shift;i++){
stdout.write(i); // or directly print(i);
}
}
void main(){
//warm up:
f(3);
// the test
f(25);
stdout.close();
}
Nicolas

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