Introduction to Software Engineering

Software Engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software. It is not just about writing code; it encompasses the entire lifecycle of a software product, from inception to retirement.

The Software Crisis

In the late 1960s, the term “Software Crisis” was coined to describe the difficulties in writing efficient, error-free, and maintainable software. Projects were frequently over budget, behind schedule, and failed to meet user requirements. This led to the realization that software development needed to transition from a “craft” to an “engineering discipline.”

Core Principles

1. Maintainability: Software should be written in such a way that it can evolve to meet changing needs.
2. Dependability: Software must be reliable, secure, and safe.
3. Efficiency: Software should not make wasteful use of system resources.
4. Usability: Software must be usable by the users for whom it was designed.

Software Engineering vs. Computer Science

While Computer Science focuses on the theory and fundamentals of computation (algorithms, data structures, complexity), Software Engineering focus on the practicalities of developing and delivering useful software.

Example: Managing Complexity

One of the primary goals of software engineering is to manage complexity. As systems grow, they become harder to understand. We use tools like abstraction and modularity to break systems into smaller, manageable parts.

Modularity in Python

# A simple example of modularity by separating concerns
class UserManager:
    def __init__(self):
        self.users = []

    def add_user(self, name):
        self.users.append(name)
        print(f"User {name} added.")

class Logger:
    @staticmethod
    def log(message):
        print(f"[LOG]: {message}")

# Usage
logger = Logger()
manager = UserManager()
manager.add_user("Alice")
logger.log("Alice was added to the system.")

Professional Responsibility

Software engineers have responsibilities to their profession and to society. This includes maintaining confidentiality, being competent, and not misrepresenting their skills. Ethical considerations are paramount, especially as software controls more critical infrastructure.

The Engineering Mindset

The engineering mindset involves:

• Requirement Analysis: Understanding what the user actually needs.
• Design: Planning the structure of the system before coding.
• Testing: Rigorously verifying that the system behaves as expected.
• Evolution: Planning for long-term changes.

In the following lessons, we will dive deeper into the methodologies and design patterns that make high-quality software development possible.