Explain the meaning of subroutine.

Subroutines accept an argument, perform the necessary operation and return the value. It is a named block of code, and often the term subroutine and function are used interchangeably. Subroutine takes the PROTOTYPE as the prototype of arguments and ATTRIBUTES as the attributes of the argument. Its syntax is: sub NAME or sub NAME PROTOTYPE ATTRIBUTES when the prototypes and attributes are optional.