Math constant PI value in C

Question

Calculating PI value is one of the complex problem and wikipedia talks about the approximations done for it and says it\'s difficult to calculate PI accurately.

How

Answer 1

Depending on the library you are using the standard GNU C Predefined Mathematical Constants are here... https://www.gnu.org/software/libc/manual/html_node/Mathematical-Constants.html

You already have them so why redefine them? Your system desktop calculators probably have them and are even more accurate so you could but just be sure you're not conflicting with existing defined ones to save on compile warnings as they tend to get defaults for things like that. Enjoy!