Double comparison

Question

Can I do this in C++?

if (4<5<6)
 cout<<\"valid\"<

i.e a double comparison? Since I know that I can

boo         


        

Answer 1

Yes, you can do it, but it won't be what you expect. It's parsed as

if ( (4<5) < 6 )

which yields

if ( 1 < 6 ) 

because 4<5 evaluates to true which is promoted to 1, which yields, obviously, true.

You'll need

if ( (4<5) && (5<6) )

Also, yes, you can do

a = 1+2<3+4<5>6;

but that as well is parsed as

a = ((1+2)<((3+4)<5))>6;

which will evaluate to false since (1+2)<((3+4)<5) yields a boolean, which is always smaller than 6.