_int64 : cin and cout

[Guysl]

how do I use cin/cout with _int64 type?

[Guysl]

does the following overload make sense?

ostream& operator<<(ostream& out, const unsigned _int64& Int64)
{
char strVal[34];
_ui64toa (Int64,strVal,10);
out << strVal;
return out;
}

[jlou]

cin and cout recognize __int64 for me just fine:#include <iostream>
int main()
{
__int64 myInt = 9223372036854775807;
std::cout << "Big number: " << myInt << std::endl;
}That works fine in MSVC++ 6.0. If you are using the old, non-standard header (<iostream.h>) then it will give you an error. Just switch to the new headers.

[Guysl]

Thanks for the reply.
I am using <iostream>, but I keep getting the error:
error C2593: 'operator <<' is ambiguous.
any idea?

Regards,
Guy

[kasracer]

Post the code you're using to print an _int64

[Guysl]

#include <iostream>

int main(int argc, char*argv[])
{
__int64 myInt = 9223372036854775807;
std::cout << "Big number: " << myInt << std::endl;

return 0;
}


I have a general problem with iostream, since I cant std::cout<<string(), but I have to use std::cout<<string().c_str()


Regards,
Guy

[jlou]

I get the same error (error C2593: 'operator <<' is ambiguous) only if I use <iostream.h> instead of <iostream>.

I also personally use a different standard library implementation from Dinkumware than the one that ships with VC++ 6. I didn't see anything in their documentation about fixing it for __int64, though. I also think that strings should print fine with the proper headers in any version.

Did you get any other errors or warnings (even unrelated) with the code you compiled?

[kasracer]

I get a different error with MinGW. it says your number is too large for a long. Nothing about an ambiguous call

:confused:

[Guysl]

kasracer,
try __int64 myInt = 9223372036854775807I64

[Guysl]

I reinstalled VC++, and problems I had with <iostream> are fixed, but still, I get 'operator <<' is ambiguous' when using __int64.
does anyone except jlou that uses Dinkumware, can make it work?

Thanks in advance,
Guy

[kasracer]

Originally posted by Guysl
kasracer,
try __int64 myInt = 9223372036854775807I64 invalid integer suffix

[Guysl]

apparently, on VC++ 6 this case is reported as a bug.
The workaround is overloading operator<<.

link:
http://support.microsoft.com/default.aspx?scid=kb;en-us;168440

[Mick]

http://www.kbalertz.com/Feedback_168440.aspx as stated somewhere up above in a reply.

[Mick]

Originally posted by Guysl
apparently, on VC++ 6 this case is reported as a bug.
The workaround is overloading operator<<.

link:
http://support.microsoft.com/default.aspx?scid=kb;en-us;168440

meh beat me too it :p

[kasracer]

Time to upgrade from the crap-tastic compiler! :p

[Guysl]

Mick,

it was me above that used that workaround, at that time
I thought its was silly... :D

operator>> overloading though, is more dirty. should I parse
a temporary string for non-digit characters and raise exception if
I find any?

[Mick]

Originally posted by Guysl
operator>> overloading though, is more dirty. should I parse
a temporary string for non-digit characters and raise exception if
I find any?

Not sure what you mean, your just providing an overload for the _int64 type. Non-digit? Exceptions?

[Guysl]

I need to overload istream operator>> for __int64 type as well,
so I guess I have to implement legality checks.

[dude_1967]

Yeah,

There is a mild compiler issue here, as indicated by others.

My standard solution is to just check for the compiler version and implement a workaround similar to the described workaround from the Microsoft page.

This workaround, written in this fashion is then 'portable', in that only the relevant compiler gets the workaround.

Sincerely, Chris.



#if defined(_MSC_VER) && (_MSC_VER <= 1200)

// Overwrite global operators << and >> for MSVC 6.0 with 64-bit integer type.
inline std::ostream& operator<<(std::ostream& os, const __int64& n)
{
char c[20];
::_i64toa(n, c, 10);
return os << c;
}

inline std::istream& operator>>(std::istream& is, __int64& n)
{
char c[20];
is >> c;
n = ::_atoi64(c);
return is;
}

#endif // IOstream fix for MSVC6

[Guysl]

Thanks Chris. :thumb:


Regards,
Guy