Subroutines and Structured Programming

Subroutine

A named 'out of line' block of code that can be executed by simply writing its name in a program statement.

Procedures

Subroutines that perform actions but do not return a value.

Functions

Subroutines that perform actions and return a value.

Code Reusability

Writing code once and using it multiple times without rewriting.

Modularity

Breaking programs into manageable sections where each subroutine performs a specific task.

Simplified Maintenance

Easier updating and fixing of code with changes in a subroutine affecting all calls to it.

Improved Readability

Making code more organized and understandable by giving structure and clarity.

Enhanced Collaboration

Allowing different programmers to work on different subroutines simultaneously, particularly useful in large projects.

Parameters

Variables listed as part of a subroutine's definition to pass data into the subroutine.

By Value

Passing a copy of the data to the subroutine.

By Reference

Passing a reference to the actual data, allowing modifications.

Returning a Value

Subroutines can return a value to the calling routine using the return statement.

Local Variables

Variables declared within a subroutine, accessible only within that subroutine.

Encapsulation

Keeping variables confined to the subroutine to prevent interference with other parts of the program.

Memory Management

Local variables are automatically destroyed when the subroutine finishes execution.

Structured Approach

A method of programming that emphasizes breaking a program into smaller, manageable, and reusable modules or subroutines.

Modularization

Dividing the program into distinct subroutines.

Clear Interfaces

Using parameters and return values to define clear inputs and outputs for subroutines.

Documentation

Well-documented code with comments and clear variable names.

Improved Code Organization

Making large programs easier to understand and manage through a structured approach.

Enhanced Debugging and Testing

Easier testing of individual modules for improved debugging.

Facilitates Teamwork

Enabling different team members to work on separate modules simultaneously.

Scalability

Simplifying the process of adding new features or making changes.

Reuse of Code

Reusing subroutines in different parts of the program or in different programs.