Re: "Linus Torvalds Was (Sorta) Wrong About C++"

From:

Paavo Helde <myfirstname@osa.pri.ee>

Newsgroups:

comp.lang.c++

Date:

Thu, 12 Mar 2015 01:27:11 -0500

Message-ID:

<XnsA45B55FBBB00Cmyfirstnameosapriee@216.196.109.131>

JiiPee <no@notvalid.com> wrote in
news:oD2Mw.1187176$6k.1000747@fx09.am4:

On 11/03/2015 21:15, Paavo Helde wrote:

JiiPee <no@notvalid.com> wrote in
news:Ie1Mw.381530$dX1.143786@fx21.am4:

int size = 10;
int* a = new int[size ];
float* b = new float[size ];
double* c = new double[size ];

This is not exactly equivalent to std::vector because the capacity
and efficient dynamic resizing are missing.

ok but lets assume that project does not need them here....

so in C we need total : 4 bytes overhead

16 bytes, if you want to compare correctly. Each pointer is an
overhead. And if you add capacities, it will make 28 bytes.

yes, forgot them. we dont add capacity....

in C++:
vector<int> a = ...10);
vector<float> b = ...10);
vector<double> c = ..10).;

would need total: 36 bytes of overhead

If the vectors are always of the same length, then the solution is
clear:

struct X {
          int a;
          float b;
          double c;
};

std::vector<X> x;

Voila: this has 12 bytes overhead,

which is 4 bytes less than the C

But if you use the same struct with C (which would be fair here), then
you get:

int size = 10;
X* x = new X[size];

With 8 bytes overhead.

And losing all the other goodies. This should be at least wrapped in a
proper RAII class whose destructor calls delete[].

Thankfully, my last experience with a computer where saving 4 bytes was
important was with Elektronika MK-61, 30 years ago.