C language question

Question

For my practice i took a calculator app for practice where in if statement there is DBX max what does it do and how it came. I Googled but it didnt worked.. Line 31
https://sololearn.com/compiler-playground/cVgx4GezkW19/?ref=app

Answer 1

DBL_MAX is the maximum float that can be represented. As I understand your code, it seems you want to use DBL_MAX to indicate an invalid result due to inappropriate user input?

Answer 2

It is a constant.

Answer 3

Axxcii, I understand your confusion and wish to let you know that this happens to everyone especially when one is not aware of all the keywords.

In C, keywords are certain predefined reserved words that are part of the language syntax and have special meaning to the compiler. So, they cannot be used as identifiers. For example, int, struct,static, double etc.

DBL_MAX is a macro constant defined in the C standard library header <float.h>. It expands to the maximum finite value that can be stored in a variable of type double on the target machine. Note that for DBL_MAX to work you need to write:
#include <float.h>

Answer 4

Lisa is DBL_MAX is an keywords?