Question

Here is some “bad” code:

Module test
    Sub Main()
        Console.WriteLine("1<2 =   " + cstr((1<2)))
        Console.WriteLine("2<1 =   " + cstr((2<1)))
        Console.WriteLine("1<2<3 = " + cstr((1<2<3)))
        Console.WriteLine("3<2<1 = " + cstr((3<2<1)))
    End Sub
End Module

The output from this is:

1<2 =   True
2<1 =   False
1<2<3 = True
3<2<1 = True

1<2<3 is True, but not for the right reasons.

3<2<1 evaluates to True as well. Why?

Can someone explain what’s going on here?

I know I should be using a<b and b<c but I want to know what happens when you use consecutive operators. ie, why doesn’t the compiler cry!! Is syntax like this used for something else?

Answer 1

It evaluates it left to right, so 3<2<1 is the same as (3<2)<1. Because expression in parentheses is false, the whole thing evaluates to 0<1 which is true.