sqrt function

[freudian_slip]

For some weird odd reason, sqrt(2/num) does not work.

cout << "   sqrt(2): " << sqrt(2) << endl;
			cout << "   sqrt(num): " << sqrt(num) << endl;
			cout << "   sqrt(2)/sqrt(num): " << sqrt(2)/sqrt(num) << endl;
			cout << "     sqrt(2/num): " << sqrt(2/num) << endl;

results in

sqrt(2): 1.41421
   sqrt(num): 2.82843
   sqrt(2)/sqrt(num): 0.5
     sqrt(2/num): 0

Can anybody tell me why? I am currently using sqrt(2)/sqrt(num) but I can't really think of a good reason why sqrt(2/num) shoudn't work..

[vmanes]

sqrt() takes only floating point values as its argument, so I'm curious what compiler you're using that accepts the ints.

That said, the division 2/num (I'm assuming num is assigned value 8) results in value 0 (zero) being passed to sqrt( ).

Remember, the result of dividing one int by another will always be an int - no fractional part. So, to do what what you seem to be attempting:

cout << sqrt( double(2)/num );

will typecast the 2 to a double, num will be implicitly promoted as well, giving the value you expect.

[freudian_slip]

I'm using gcc version 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)

Thanks for the tip, I did try casting double but I guess I typecasted double(2/num) instead of double(2)/num. Thanks again!

[vmanes]

Well, that looks like another non-standard thing gcc has implemented.

Any gcc gurus care to chime in?