Boolean operators work on anything that are boolean expressions. Boolean expressions is anything that can be expressed as true or false. That means they are not just limited to integers. Example: MyString == "Hello World" is a boolean expression.
Originally Posted by Adak
io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
Originally Posted by Salem
You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.
Outside of your DOS world, your header file is meaningless.