Just would like to share something. For months I couldn't decide
what language to use for my pet project, analysed dozens of
languages from rust to go and I always fell back to C++
(performance is critical for me). After rust I had a look at
DLang but as a C++ veteran I had my (wrong) feelings, prejudices
etc but I got infected and started to go down a long route of
trying to accept it and trying to love it. I am a slow learner
but forced to open my mind. I am also a Python dev so I kinda
liked the syntax and the simplicity of the language, the speed of
compilation and execution was also appealing but still... But
then something has happened which basically helped to make up my
mind and to go with D finally.
From the Programming in D book i typed in the below code, I use
Sublime.
```
import std.stdio : writeln;
void main()
{
int[12] months = [ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31,
30, 31 ];
int[] first = months[0 .. 3];
int[] second = months[3 .. 6];
int[] third = months[6 .. 9];
int[] fourth = months[9 .. 12];
writeln(first);
writeln(second);
writeln(third);
writeln(fourth);
}
```
Then I have decided to reimplement this in C++. The code is not
perfect hacked it together on the train. The length and the
complexity is already on the negative side.
#include <iostream>
#include <array>
#include <iterator>
using namespace std;
template<class X, class Y>
X slice(const Y& src, const size_t start, const size_t end)
{
X dst;
std::copy(src.begin() + start, src.begin() + end,
dst.begin());
return dst;
}
template <class T, std::size_t N>
ostream& operator<<(ostream& o, const array<T, N>& arr)
{
std::cout << "[";
for (auto& elem : arr) {
std::cout << elem;
if (&elem != &arr.back()) printf(", ");
}
std::cout << "]";
return o;
}
int main() {
array<int, 12> _arr = { 31, 28, 31, 30, 31, 30, 31, 31,
30, 31, 30, 31 };
array<int, 3> first = slice<decltype(first)>(_arr, 0, 3);
array<int, 3> second = slice<decltype(second)>(_arr, 3,
6);
array<int, 3> third = slice<decltype(third)>(_arr, 6, 9);
array<int, 3> fourth = slice<decltype(fourth)>(_arr, 9,
12);
cout << first << endl;
cout << second << endl;
cout << third << endl;
cout << fourth << endl;
}
Then came the performance test, here we go:
Performance test:
rvinMacBookProLimegg:source ervinbosenbacher$ time ./app
[31, 28, 31]
[30, 31, 30]
[31, 31, 30]
[31, 30, 31]
real 0m0.004s
user 0m0.001s
sys 0m0.001s
ErvinMacBookProLimegg:source ervinbosenbacher$ time ./a.out
[31, 28, 31]
[30, 31, 30]
[31, 31, 30]
[31, 30, 31]
real 0m0.004s
user 0m0.001s
sys 0m0.002s
That is the same, that came as a shock to me.
Happy coding al!
