What is the difference between \n and std::endl ?

Question

is there any different performance advantage between \n and std::endl?
if i want to output a large file like a briefing page through network , which one better?

Answer 1

@Setiawan Next

Here is a test I just did, the results were:

Test A time in ms: 790
Test B time in ms: 124

So in conclusion, \n really is much faster.

#include <fstream>
#include <ctime>
#include <iostream>

void funcA(unsigned len)
{
std::ofstream file("testA.txt");

time_t start = clock();

for (unsigned i = 0; i < len; i++)
{
file << "aaa" << std::endl;
}

std::cout << "Test A time in ms: " << clock() - start << "\n";
}

void funcB(unsigned len)
{
std::ofstream file("testB.txt");

time_t start = clock();

for (unsigned i = 0; i < len; i++)
{
file << "aaa" << "\n";
}

std::cout << "Test B time in ms: " << clock() - start << "\n";
}

int main()
{
unsigned len = 100000;

funcA(len);
funcB(len);
}

Answer 2

@Ulisses. Nice link. Provides additional info ontop of the answer provided aklex

@Setiawan: Is this another question from your teacher? If so I feel he is slowly becoming mine also! Keep up the questions!

Answer 3

@aklex: wow. not even apples and oranges.. more like apples and bricks.. didnt think it would make that much difference.

Answer 4

http://www.cplusplus.com/forum/beginner/7350/

Answer 5

Endl flushes the stream and starts a new line
\n just starts a new line

Use \n unlesss you need to flush as it's much faster

Answer 6

@aklex
Thank You very much, i know \n is faster but i can not prove it. Your explanation is really helpful.

@jay
no, i figure it out by myself. my teacher give me one quizz each time he meet me. and i don't meet him today, not yet.