Boolean Values in C++

Boolean expressions are evaluated from left to right (the same in Java), so it is totally OK to write code like

 if(a < x.size() && x[a]){
     ...
 }

where x is a vector.

There is no &&= and ||= operators in C++, instead you can use &= and |=. Though &= and |= are not specially for boolean values, they work perfectly for boolean values.

If the numbers you work with support infinity or NaN, boolean expressions become tricky. For example, suppose nan is a varialbe representing Nan, both 2 < nan and 2 >= nan return false, which is not what we want. A safer way is to first check whether numbers involved are NaNs. Hopefully, ternary boolean type will be introduced into C++ in future.