What is "double" exactly for, in C?

Question

The compiler warns : "format '%lf' expects argument of type 'double *', but argument 2 has type 'double' "

Answer 1

To simply answer your initial question, a double is a double precision floating point number capable of representing a number with more precision/accuracy using more numbers after the decimal point than single precision floats.

Answer 2

Martin Taylor yes , you are right that's exactly what I did , I start forgetting basic things😁. Thank you so much that's really strength my bad knowledge ❤❤