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Why do we have map, fmap and liftM?
... see an error about lists than about Functors.
-- Typeclassopedia, page 20
fmap and liftM exist because monads were not automatically functors in Haskell:
The fact that we have both fmap and liftM is an
unfortunate consequence of the fact that the Monad type class does not require
a Funct...
What does |= (single pipe equal) and &=(single ampersand equal) mean
... |
edited Dec 24 '19 at 0:20
djeikyb
3,87233 gold badges3030 silver badges3737 bronze badges
answered ...
How to sum up elements of a C++ vector?
...
Actually there are quite a few methods.
int sum_of_elems = 0;
C++03
Classic for loop:
for(std::vector<int>::iterator it = vector.begin(); it != vector.end(); ++it)
sum_of_elems += *it;
Using a standard algorithm:
#include <numeric>
sum_of_elems = std::accu...
How to redirect the output of an application in background to /dev/null
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edited Apr 13 '17 at 21:20
answered Nov 21 '11 at 23:40
ev...
Installing Latest version of git in ubuntu
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edited Jan 4 '18 at 6:40
Quanlong
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answered Oc...
Git production/staging server workflow
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answered Oct 2 '10 at 4:34
bUg.bUg.
91299 silver badges1111 bronze badges
...
Creating my own Iterators
...rs. I have written an article about this very topic; it's in the December 2008 ACCU magazine. It discusses an (IMO) elegant solution for exactly your problem: exposing member collections from an object, using Boost.Iterators.
If you want to use the stl only, the Josuttis book has a chapter on imple...
How to stop Eclipse formatter from placing all enums on one line
... RUNNING,
WAITING,
FINISHED
}
enum Example {
GREEN(
0,
255,
0),
RED(
255,
0,
0)
}
Solution described above:
enum Example {
CANCELLED,
RUNNING,
WAITING,
FINISHED
}
enum Example {
GREEN(0, 255, 0),
RED(255, ...
How to merge two sorted arrays into a sorted array? [closed]
...
Sumit Singh
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answered May 11 '11 at 1:19
Greg HewgillGreg Hewgill
...
Why is my program slow when looping over exactly 8192 elements?
...for(i=1;i<SIZE-1;i++)
for(j=1;j<SIZE-1;j++) {
res[j][i]=0;
for(k=-1;k<2;k++)
for(l=-1;l<2;l++)
res[j][i] += img[j+l][i+k];
res[j][i] /= 9;
}
First notice that the two inner loops are trivial. They can be unrolled as follows:
f...