Adding up values in a list

Question

I have a little question. How do I do to sum up all the numbers in a list packs? For example: List 1 is :

I want to sum up all the numbers.

[`std::accumulate`](http://en.cppreference.com/w/cpp/algorithm/accumulate) — BoBTFish, Oct 30 '13 at 14:16
Specify, input data type of list, maybe try to write some code, that have to do your task. Begin to solve your problem yourself, we'll help. — Oleg Olivson, Oct 30 '13 at 14:18

digital_revenant · Answer 1 · 2013-10-30T14:23:05.783

6

Use std::accumulate. It will return the arithmetic sum of all the elements in the list.

double sum = std::accumulate(std::begin(list), std::end(list), 0.0);

edited Oct 30 '13 at 14:23

answered Oct 30 '13 at 14:17

digital_revenant

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Thanks a lot for the propositions. I found an easier method by try and error. double result = sum(myList()); Info <<"sum is: "<< result<< endl; – chofor marius Oct 30 '13 at 14:25
@choformarius With this method you don't have to define your own `sum` function. – digital_revenant Oct 30 '13 at 14:27
I wouldn't consider writing the function myself easier than using the function provided by the Standard Library specifically for this purpose. Also, do yourself a favour, and stop using [`using namespace std;`](http://stackoverflow.com/q/1452721/1171191) and [`std::endl`](http://kuhllib.com/2012/01/14/stop-excessive-use-of-stdendl/). – BoBTFish Oct 30 '13 at 14:29

Mustakimur Khandaker · Answer 2 · 2013-11-02T13:02:41.110

1

Do the same like following:

double sum=0;
for (std::list<double>::iterator it=mylist.begin(); it != mylist.end(); ++it){
    sum+=*it;
}

Hope it may help you :)

edited Nov 02 '13 at 13:02

answered Oct 30 '13 at 14:19

Mustakimur Khandaker

715
6
24

1

I am wondered why someone give downvote on my answer, is there anything wrong in my answer, please comment then, I want to learn, not to earn point :) – Mustakimur Khandaker Oct 30 '13 at 14:31
I think someone gave you a downvote probably because the numbers in OP's list are of type `double` whereas you declare `int sum` – digital_revenant Oct 30 '13 at 14:49
@MustakimurRahman: then, edit you answer and give the downvoter the chance to undo his vote. – masoud Nov 02 '13 at 06:38
okay, I did it :) but not for upvote, to give a correct answer :D Thanks @MM. – Mustakimur Khandaker Nov 02 '13 at 13:03
@MustakimurRahman: I wasn't the down-voter anyway +1 for your attention to comments. – masoud Nov 02 '13 at 15:28

score 0 · Answer 3 · answered Oct 30 '13 at 14:17

0

Assuming you're using std::list,

double total = 0;
for (std::list<double>::const_iterator iterator = list1.begin(), end = list1.end(); iterator != end; ++iterator) {
    total += *iterator;
}
return total;

answered Oct 30 '13 at 14:17

Kvothe

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Adding up values in a list

3 Answers3