Subroutines

Subroutine

A named set of instructions executed when called.

Procedure

A subroutine that performs a task without returning values.

Function

A subroutine that returns one or more values.

Built-in functions

Predefined functions in programming languages for common tasks.

Library subroutines

Predefined subroutines available through imported modules.

Parameters

Variables in subroutine definitions that accept input.

Arguments

Values passed to subroutines during calls.

Passing by value

Copies argument value to parameter, no changes affect original.

Passing by reference

Passes address of argument; changes affect original value.

Local variable

Defined within a subroutine, inaccessible outside it.

Global variable

Defined in the main program, accessible in any subroutine.

Scope of variable

The context in which a variable is accessible.

Modular programming

Breaking down tasks into smaller, manageable subtasks.

Advantages of local variables

Prevents accidental changes to main program variables.

Advantages of modular programming

Easier debugging, testing, and program management.

Return statement

Used in functions to send values back to caller.

Procedure call

Execution of a subroutine from the main program.

Function call

Execution of a function that returns a value.

Subroutine execution flow

Program jumps to subroutine, then returns to caller.

Parameter order

Sequence of parameters matters in subroutine calls.

Example of built-in function

sqrt(num) computes the square root of num.

Example of library subroutine

random.randint(1,6) generates a random integer.

Output of multiply(2,5)

Displays the product of 2 and 5.

Variable initialization

Assigning initial values to variables before use.

Function returning multiple values

A function can return several outputs using tuples.

Independent subroutines

Subroutines that can be reused across different programs.

Subroutine definition

Specifies parameters and instructions for a subroutine.

Error in variable scope

Accessing a local variable outside its defined scope.