Dynamic sized array?

[Daniel T.]

I recently came across something like the following:

int main() {
unsigned i;
cin >> i;
int arr;
// use arr
}

Is that valid in C++? I thought it was only valid in C99...

 

[Kai-Uwe Bux]

I recently came across something like the following:

int main() {
unsigned i;
cin >> i;
int arr;
// use arr
}

Is that valid in C++?

No. However, some compiler accept it as an extension. However, a diagnostic
is required: if the compiler accepts it, you should still get a warning.

I thought it was only valid in C99...

I don't know about C99.


Best

Kai-Uwe Bux

 

[Martin Steen]

I recently came across something like the following:

int main() {
unsigned i;
cin >> i;
int arr;
// use arr
}

Is that valid in C++? I thought it was only valid in C99...

No, it's not valid. Although some compilers (e.g. g++) may
compile it.

If you want dynamic arrays, better use vector-templates from the STL:

#include <vector>

int main()
{
unsigned i;
cin >> i;
std::vector<int> arr(i);
// use arr
return 0;
}

-Martin

 

[Sumit Rajan]

I recently came across something like the following:

int main() {
unsigned i;
cin >> i;
int arr;
// use arr
}

Is that valid in C++?

No/Not yet.

I thought it was only valid in C99...

Yes, it is valid in C99.

Regards,
Sumit.

 

[Sumit Rajan]

Yes, it is valid in C99.

Of course, "cin" wouldn't be around in such a case.

Sumit.