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In my code abs() isnt working but when put in a different code editor it does work. I dont know what to do. Cant find answers anywhere. Please help. Error: ("abs" is ambiguousC/C++(266))

#include <iostream>
#include <cstdlib>

using namespace std;

int main(){

    int x = -1;
    int a = abs(x);

    cout<< a;

}
Marcelo Casanova
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    Is taht a message from your compiler or IDE? – R Sahu Sep 09 '20 at 04:54
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    Removing the `using` and writing `std::abs` might remove that IDE warning. – Quimby Sep 09 '20 at 04:55
  • Probably related, if not the answer: https://stackoverflow.com/questions/35378761/error-with-abs-in-c – Tas Sep 09 '20 at 04:58
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    Recommended reading: [Why is “using namespace std;” considered bad practice?](https://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice) – user4581301 Sep 09 '20 at 05:03
  • The error is not related to abs() itself, but it is a code quality issue detected by the C/C++ extension by Microsoft for the Visual Studio Code editor. (please add this note to the question when S.O. will allow edition again later - it's currently overflowed...) – Chucky Jan 16 '23 at 11:26

3 Answers3

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More information will be helpful. There's no need to add "using namespace std" here. You can try to modify "int a = abs(x);" ==> "int a = ::abs(x);"

Paul Wang
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  • `#include `, as written in the question, is required to put all the names into `std`, and it is **allowed** to put the names into the global namespace. So `::abs` isn’t required to work. `std::abs` will see all the names. To use `::abs`, the appropriate header is `#include `, which puts all the names into the global namespace and is **allowed** to put the names into `std`. – Pete Becker Sep 09 '20 at 19:26
  • I did above test on Visual Studio 2019(C++17 ), and it works fine. Actually, cstdlib has already included the stdlib.h – Paul Wang Sep 10 '20 at 12:27
  • Yes, that’s the point: it **might** work; it is not **required** to work. Not even in a future version of a compiler for which it now works. – Pete Becker Sep 10 '20 at 14:56
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#include <iostream>
#include <cstdlib>

using namespace std;

int main(){

    int x = -1;
    int a = fabs(x);

    cout<< a;

}

or


#include <iostream>
#include <stdlib.h>


int main() {

    int x = -1;
    int a = abs(x);

    std::cout << a;

}
harkhuang
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0

As commented earlier under the question, the error is not related to abs() itself: it's a code quality issue detected by the C/C++ extension by Microsoft for the Visual Studio Code editor which is somewhat inappropriate.

Workaround:

[The] error description go away if I either a) make the namespace explicit at the site of the supposed error (not that this is always desirable) or b) edit the definition and declaration to make them temporarily invalid and then edit them back (not that this leaves me confident that the squiggle won't come back).

Source: https://developercommunity.visualstudio.com/t/showing-error-is-ambiguous-even-though-the-code-co/405607

Chucky
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