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Who Needs C++ When
You Have D and Go?

Russel Winder
email: russel@winder.org.uk
xmpp: russel@winder.org.uk
twitter: @russel_winder
Web: http://www.russel.org.uk

Copyright © 2013 Russel Winder 1

controversy
noun
dispute, argument, or debate, especially one
concerning a matter about which there is
strong disagreement


Calculate the sum of the squares of the
numbers between 0 and 100 that are
divisible by 7.


int sequential_iterative() {
auto sum = 0;
foreach (i; 0 .. 100) {
if (i % 7 == 0) {
sum += i * i;
}
}
return sum;
}


func sequential_iterative() (sum int) {
for i := 0; i < 100; i++ {
if (i % 7 == 0) {
sum += i * i
}
}
return
}


int sequential_iterative() {
auto sum = 0;
for (auto i = 0; i < 100; ++i) {
if (i % 7 == 0) {
sum += i * i;
}
}
return sum;
}


So all native code programming
languages are the same?


We are, of course, expected
to be more declarative these days…


Possibly even functional…


reduce!"a + b"(map!"a * a"(filter!"a % 7 == 0"(iota(100))))


functools.Inject(func (a, b int) int { return a + b },
functools.Collect(func (i int) int { return i * i },
functools.Filter(func (i int) bool { return i % 7 == 0 },
make([]int, 100))))


int sequential_declarative() {
std::vector<int> numbers (100);
std::iota(numbers.begin(), numbers.end(), 1);
std::list<int> filtered;
std::copy_if(numbers.begin(), numbers.end(),
std::back_insert_iterator<std::list<int>>(filtered), [=] (int i) { return i % 7 == 0; });
std::vector<int> squares (filtered.size());
std::transform(filtered.begin(), filtered.end(),
std::back_insert_iterator<std::vector<int>>(squares), [=] (int i) { return i * i;});
return std::accumulate(squares.begin(), squares.end(), 0, [=] (int i, int j) { return i + j;});
}


What about being fluent…


iota(100).filter!"a % 7 == 0"().map!"a * a"().reduce!"a + b"()


functools.IntSlice(make([]int, 100)).
Filter(func (i int) bool { return i % 7 == 0 }).
Collect(func (i int) int { return i * i }).
Inject(func (a, b int) int { return a + b })


?


Execute it!


Use D
Use Go

Use Python

Anything but C++


http://www.dlang.org

http://www.go-lang.org


Who Needs C++ When
You Have D and Go?

Russel Winder
email: russel@winder.org.uk
xmpp: russel@winder.org.uk
twitter: @russel_winder
Web: http://www.russel.org.uk


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Who needs C++ when you have D and Go

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