Why are parameters important in programming?

Parameters are used to pass or assign values to an operation or routine at run time.

These are often used where an executable file is used in order for the user to direct the operation of the routine, but without changing the code of the executable or recompiling it.

For example parameters are used extensively in old MS DOS (compiled) executables in order to to provide different result (without changing the code of the executable).

The DIR (Directory) command for example:

DIR

DIR *.exe / DIR *.txt

DIR /P

DIR /W

DIR /A

All use the same executable (DIR), but provide the user with different sets of output