In C++, am I paying for what I am not eating?

up vote
7
down vote

favorite

Let's consider the following hello world examples in C and C++ :

main.c

#include <stdio.h>

int main()

 printf("Hello worldn");
 return 0;

main.cpp

#include <iostream>

int main()

 std::cout<<"Hello world"<<std::endl;
 return 0;

When I compile them in godbolt to assembly, the size of the C code is only 9 lines (gcc -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edi, OFFSET FLAT:.LC0
 call puts
 xor eax, eax
 add rsp, 8
 ret

But the size of the C++ code is 22 lines (g++ -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edx, 11
 mov esi, OFFSET FLAT:.LC0
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)
 xor eax, eax
 add rsp, 8
 ret
_GLOBAL__sub_I_main:
 sub rsp, 8
 mov edi, OFFSET FLAT:_ZStL8__ioinit
 call std::ios_base::Init::Init() [complete object constructor]
 mov edx, OFFSET FLAT:__dso_handle
 mov esi, OFFSET FLAT:_ZStL8__ioinit
 mov edi, OFFSET FLAT:_ZNSt8ios_base4InitD1Ev
 add rsp, 8
 jmp __cxa_atexit

which is much larger.

It is famous that in C++ you pay for what you eat. So, in this case, what am I paying for?

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

3

You pay for initializing std::cout.
â€“Â Yksisarvinen
54 mins ago

2

For using iostream. In this case for std::cout.
â€“Â P.W
53 mins ago

3

It's a myth that C++ is equally efficient as C, simple as that. Such believes only work in theory but rarely in practice. That being said, this question isn't answerable unless you post your optimization settings for each compiler.
â€“Â Lundin
50 mins ago

3

@Lundin: there's nothing preventing C++ from being as fast as C. Standard Libraries are another matter.
â€“Â Vittorio Romeo
49 mins ago

6

You are eating cout, so I don't see what you're paying for that you don't eat. That you can still your hunger with either lobster or an egg sandwich doesn't mean that you get to buy the lobster for the same price as an egg sandwich if your goal is just to not be hungry.
â€“Â molbdnilo
45 mins ago

Â |Â
show 9 more comments

up vote
7
down vote

favorite

Let's consider the following hello world examples in C and C++ :

main.c

#include <stdio.h>

int main()

 printf("Hello worldn");
 return 0;

main.cpp

#include <iostream>

int main()

 std::cout<<"Hello world"<<std::endl;
 return 0;

When I compile them in godbolt to assembly, the size of the C code is only 9 lines (gcc -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edi, OFFSET FLAT:.LC0
 call puts
 xor eax, eax
 add rsp, 8
 ret

But the size of the C++ code is 22 lines (g++ -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edx, 11
 mov esi, OFFSET FLAT:.LC0
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)
 xor eax, eax
 add rsp, 8
 ret
_GLOBAL__sub_I_main:
 sub rsp, 8
 mov edi, OFFSET FLAT:_ZStL8__ioinit
 call std::ios_base::Init::Init() [complete object constructor]
 mov edx, OFFSET FLAT:__dso_handle
 mov esi, OFFSET FLAT:_ZStL8__ioinit
 mov edi, OFFSET FLAT:_ZNSt8ios_base4InitD1Ev
 add rsp, 8
 jmp __cxa_atexit

which is much larger.

It is famous that in C++ you pay for what you eat. So, in this case, what am I paying for?

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

3

You pay for initializing std::cout.
â€“Â Yksisarvinen
54 mins ago

2

For using iostream. In this case for std::cout.
â€“Â P.W
53 mins ago

3

It's a myth that C++ is equally efficient as C, simple as that. Such believes only work in theory but rarely in practice. That being said, this question isn't answerable unless you post your optimization settings for each compiler.
â€“Â Lundin
50 mins ago

3

@Lundin: there's nothing preventing C++ from being as fast as C. Standard Libraries are another matter.
â€“Â Vittorio Romeo
49 mins ago

6

You are eating cout, so I don't see what you're paying for that you don't eat. That you can still your hunger with either lobster or an egg sandwich doesn't mean that you get to buy the lobster for the same price as an egg sandwich if your goal is just to not be hungry.
â€“Â molbdnilo
45 mins ago

Â |Â
show 9 more comments

up vote
7
down vote

favorite

Let's consider the following hello world examples in C and C++ :

main.c

#include <stdio.h>

int main()

 printf("Hello worldn");
 return 0;

main.cpp

#include <iostream>

int main()

 std::cout<<"Hello world"<<std::endl;
 return 0;

When I compile them in godbolt to assembly, the size of the C code is only 9 lines (gcc -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edi, OFFSET FLAT:.LC0
 call puts
 xor eax, eax
 add rsp, 8
 ret

But the size of the C++ code is 22 lines (g++ -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edx, 11
 mov esi, OFFSET FLAT:.LC0
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)
 xor eax, eax
 add rsp, 8
 ret
_GLOBAL__sub_I_main:
 sub rsp, 8
 mov edi, OFFSET FLAT:_ZStL8__ioinit
 call std::ios_base::Init::Init() [complete object constructor]
 mov edx, OFFSET FLAT:__dso_handle
 mov esi, OFFSET FLAT:_ZStL8__ioinit
 mov edi, OFFSET FLAT:_ZNSt8ios_base4InitD1Ev
 add rsp, 8
 jmp __cxa_atexit

which is much larger.

It is famous that in C++ you pay for what you eat. So, in this case, what am I paying for?

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

Let's consider the following hello world examples in C and C++ :

main.c

#include <stdio.h>

int main()

 printf("Hello worldn");
 return 0;

main.cpp

#include <iostream>

int main()

 std::cout<<"Hello world"<<std::endl;
 return 0;

When I compile them in godbolt to assembly, the size of the C code is only 9 lines (gcc -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edi, OFFSET FLAT:.LC0
 call puts
 xor eax, eax
 add rsp, 8
 ret

But the size of the C++ code is 22 lines (g++ -O3):

.LC0:
 .string "Hello world"
main:
 sub rsp, 8
 mov edx, 11
 mov esi, OFFSET FLAT:.LC0
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)
 mov edi, OFFSET FLAT:_ZSt4cout
 call std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)
 xor eax, eax
 add rsp, 8
 ret
_GLOBAL__sub_I_main:
 sub rsp, 8
 mov edi, OFFSET FLAT:_ZStL8__ioinit
 call std::ios_base::Init::Init() [complete object constructor]
 mov edx, OFFSET FLAT:__dso_handle
 mov esi, OFFSET FLAT:_ZStL8__ioinit
 mov edi, OFFSET FLAT:_ZNSt8ios_base4InitD1Ev
 add rsp, 8
 jmp __cxa_atexit

which is much larger.

It is famous that in C++ you pay for what you eat. So, in this case, what am I paying for?

c++ c

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

edited 39 mins ago

Lundin

101k16147251

edited 39 mins ago

Lundin

101k16147251

edited 39 mins ago

Lundin

101k16147251

asked 55 mins ago

Saher

391

New contributor

asked 55 mins ago

Saher

391

asked 55 mins ago

Saher

391

New contributor

Saher is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

3

You pay for initializing std::cout.
â€“Â Yksisarvinen
54 mins ago

2

For using iostream. In this case for std::cout.
â€“Â P.W
53 mins ago

3

It's a myth that C++ is equally efficient as C, simple as that. Such believes only work in theory but rarely in practice. That being said, this question isn't answerable unless you post your optimization settings for each compiler.
â€“Â Lundin
50 mins ago

3

@Lundin: there's nothing preventing C++ from being as fast as C. Standard Libraries are another matter.
â€“Â Vittorio Romeo
49 mins ago

6

You are eating cout, so I don't see what you're paying for that you don't eat. That you can still your hunger with either lobster or an egg sandwich doesn't mean that you get to buy the lobster for the same price as an egg sandwich if your goal is just to not be hungry.
â€“Â molbdnilo
45 mins ago

Â |Â
show 9 more comments

3

You pay for initializing std::cout.
â€“Â Yksisarvinen
54 mins ago

2

For using iostream. In this case for std::cout.
â€“Â P.W
53 mins ago

3

It's a myth that C++ is equally efficient as C, simple as that. Such believes only work in theory but rarely in practice. That being said, this question isn't answerable unless you post your optimization settings for each compiler.
â€“Â Lundin
50 mins ago

3

@Lundin: there's nothing preventing C++ from being as fast as C. Standard Libraries are another matter.
â€“Â Vittorio Romeo
49 mins ago

6

You are eating cout, so I don't see what you're paying for that you don't eat. That you can still your hunger with either lobster or an egg sandwich doesn't mean that you get to buy the lobster for the same price as an egg sandwich if your goal is just to not be hungry.
â€“Â molbdnilo
45 mins ago

You pay for initializing std::cout.
â€“Â Yksisarvinen
54 mins ago

For using iostream. In this case for std::cout.
â€“Â P.W
53 mins ago

It's a myth that C++ is equally efficient as C, simple as that. Such believes only work in theory but rarely in practice. That being said, this question isn't answerable unless you post your optimization settings for each compiler.
â€“Â Lundin
50 mins ago

@Lundin: there's nothing preventing C++ from being as fast as C. Standard Libraries are another matter.
â€“Â Vittorio Romeo
49 mins ago

You are eating cout, so I don't see what you're paying for that you don't eat. That you can still your hunger with either lobster or an egg sandwich doesn't mean that you get to buy the lobster for the same price as an egg sandwich if your goal is just to not be hungry.
â€“Â molbdnilo
45 mins ago

Â |Â
show 9 more comments

2 Answers
2

active

oldest

votes

up vote
8
down vote

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

I also want to make it clear that C++ != The C++ Standard Library. The Standard Library is supposed to be general-purpose and "fast enough", but it will often be slower than a specialized implementation of what you need.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

answered 53 mins ago

Vittorio Romeo

51.3k14137273

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

1

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

add a commentÂ |Â

up vote
3
down vote

The Input / Output functions in C++ are elegantly written and are designed so they are simple to use. In many respects they are a showcase for the object-orientated features in C++.

But you do indeed give up a bit of performance in return, but that's negligible compared to the time taken by your operating system to handle the functions at a lower level.

You can always fall back to the C style functions as they are part of the C++ standard, or perhaps give up portability altogether and use direct calls to your operating system.

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

add a commentÂ |Â

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2 Answers
2

active

oldest

votes

2 Answers
2

active

oldest

votes

up vote
8
down vote

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

answered 53 mins ago

Vittorio Romeo

51.3k14137273

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

1

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

add a commentÂ |Â

up vote
8
down vote

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

answered 53 mins ago

Vittorio Romeo

51.3k14137273

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

1

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

add a commentÂ |Â

up vote
8
down vote

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

answered 53 mins ago

Vittorio Romeo

51.3k14137273

So, in this case, what am I paying for?

std::cout is more powerful and complicated than printf. It supports things like locales, stateful formatting flags, and more.

If you don't need those, use std::printf or std::puts - they're available in <cstdio>.

It is famous that in C++ you pay for what you eat.

On the other hand, the C++ language strives to make it possible to write code without paying unnecessary extra hidden costs (e.g. opt-in virtual, no garbage collection).

answered 53 mins ago

Vittorio Romeo

51.3k14137273

answered 53 mins ago

Vittorio Romeo

51.3k14137273

answered 53 mins ago

Vittorio Romeo

51.3k14137273

answered 53 mins ago

Vittorio Romeo

51.3k14137273

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

1

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

add a commentÂ |Â

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

1

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

I think it is worth mentioning that one major advantage of streams as opposed to printf is that they can be taught to work with arbitrary types.
â€“Â lisyarus
36 mins ago

@lisyarus The format string of printf is variable, so that's a weak argument. The real advantage with iostream is rather that it's somewhat robust, while stdio is a museum of the most dangerous functions ever designed in the history of programming.
â€“Â Lundin
18 mins ago

@Lundin Yes, but you can't teach printf how to print a user-defined type instead of specifying the format every time (you can in some implementations, but, as far as I know, it is not recommended to use this feature). With streams, you can just put another overload of operator << without the need to repeat yourself. Of course, I agree that safety is another major advantage, in some cases the major one.
â€“Â lisyarus
10 mins ago

add a commentÂ |Â

up vote
3
down vote

The Input / Output functions in C++ are elegantly written and are designed so they are simple to use. In many respects they are a showcase for the object-orientated features in C++.

But you do indeed give up a bit of performance in return, but that's negligible compared to the time taken by your operating system to handle the functions at a lower level.

You can always fall back to the C style functions as they are part of the C++ standard, or perhaps give up portability altogether and use direct calls to your operating system.

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

add a commentÂ |Â

up vote
3
down vote

The Input / Output functions in C++ are elegantly written and are designed so they are simple to use. In many respects they are a showcase for the object-orientated features in C++.

But you do indeed give up a bit of performance in return, but that's negligible compared to the time taken by your operating system to handle the functions at a lower level.

You can always fall back to the C style functions as they are part of the C++ standard, or perhaps give up portability altogether and use direct calls to your operating system.

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

add a commentÂ |Â

up vote
3
down vote

The Input / Output functions in C++ are elegantly written and are designed so they are simple to use. In many respects they are a showcase for the object-orientated features in C++.

But you do indeed give up a bit of performance in return, but that's negligible compared to the time taken by your operating system to handle the functions at a lower level.

You can always fall back to the C style functions as they are part of the C++ standard, or perhaps give up portability altogether and use direct calls to your operating system.

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

The Input / Output functions in C++ are elegantly written and are designed so they are simple to use. In many respects they are a showcase for the object-orientated features in C++.

But you do indeed give up a bit of performance in return, but that's negligible compared to the time taken by your operating system to handle the functions at a lower level.

You can always fall back to the C style functions as they are part of the C++ standard, or perhaps give up portability altogether and use direct calls to your operating system.

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

edited 40 mins ago

answered 52 mins ago

Bathsheba

168k26238354

answered 52 mins ago

Bathsheba

168k26238354

answered 52 mins ago

Bathsheba

168k26238354

add a commentÂ |Â

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