The #include directive causes the source code of a second file to be inserted into the original file without having to retype the code.
Explanation:
Include is a directive that many programming languages and computer files use in order to merge the source code of one file with that of the another file without retyping the code
# include is used in programming languages like c,c++ because it includes the library functions which makes coding simpler .
For example
#include<Math.h> - is responsible for the mathematical calculations if we don,t use math.h then we will face a error in the code
