Introduction to Subprograms

Sub-programs, also known as subroutines are self-contained blocks of code that perform a specific task within a larger program. They are designed to enhance modularity, reusability, and maintainability of code. 

Subprograms are first defined within the program. Once the function has been defined it can be executing anywhere within the program by calling the function, usually be writing the subprogram name, followed parentheses.

def greeting(): #Here we define the subprogram
    print("hello world")
greeting() #Here we call the subprogram

Subprograms can be divided into two types: functions and procedures.

Functions

A function is a block of code that performs a specific task and returns a value after execution.

Functions return a result after execution, which can be used elsewhere in the program.Since functions return values, they can be used within expressions (e.g., mathematical calculations).

Example

def add(a, b):
    return a + b
result = add(3, 5)  # Returns 8

Procedures

A procedure (often called a subroutine) is a block of code that performs a task but does not return a value. Procedures do not return a result after execution; their primary goal is to carry out a task.

Procedures are often used for performing actions like printing, modifying global variables, or interacting with the user.

Example Procedure

def greet(name):
    print(f"Hello, {name}!")
greet("Maria")  # Outputs: Hello, Maria!

Advantages of subprograms - Modularity

Subprograms allow for the division of complex tasks into smaller manageable units, making the code easier to understand and maintain.

Advantages of subprograms - Reusability

Subprograms can be reused in different parts of the program or in other programs, eliminating the need for duplicating code and saving development time.

Advantages of subprograms - Abstraction

Subprograms reduce complexity by hiding the details of their implementation, allowing the programmer to focus on the high-level functionality.

Advantages of subprograms - Code organization

Subprograms help in organizing code into logical sections, making it easier to navigate and debug.