Mastering Iterative Object-oriented Development in C#

Demonstrate why iterative development demands strict design practices to avoid copy-and-paste pitfalls, defects, and poor extensibility when adding operations like subtraction and multiplication.

Explore how copy/paste programming creates duplicated code and maintenance hazards. Learn to extract abstractions, avoid code duplication, and address design flaws through iterative, emergent design.

Learn how iterative object-oriented development in C# exposes a design flaw that turns into a bug, and how introducing available numbers and reworking expression combination with LINQ predicates fixes it.

Apply emergent design on top of iterative development to decouple the design, introduce proper abstractions, and improve maintainability and performance, enabling easier feature changes.

Master iterative object-oriented development in C# by implementing an empty problem statements stream, a console problems reader, and a ReadAll method returning an empty IEnumerable<ProblemStatement> to avoid null references.

Explore iterative object-oriented development in C# by delegating tasks to specialized components, reading input from the console, and evolving emergent design through ReadAll and ConsoleProblemsReader.

Read problem statements by collecting raw numbers into a jagged array and converting each row into a problem statement. Delegate to subcomponents via ReadAll and embrace emergent design.

Create an input pipeline by adding an IncomingLines extension on TextReader to read console lines, parse digits with regular expressions into ints using LINQ, and separate domain logic from code.

Design code iteratively by creating abstractions for needs and exposing them through interfaces, abstracts, or classes that are easy to consume, and separate domain from infrastructure to support emergent design.

Explore emergent object-oriented design by iteratively separating general-purpose code from domain logic, using common namespaces, extension methods, and domain boundaries to enforce the single responsibility principle.

Explore separating domain logic from general-purpose input handling to boost performance in C# object-oriented development. Learn validation, parsing, and using console problem reader with extension methods to avoid cycle eaters.

Learn to build true pipelines by transforming each object exactly once, avoid throwing away data, and arrange stages to maximize processing efficiency and memory use in practice.

Measure time and memory to drive an efficient pipeline, preserving parsed numbers with tuples and non-negative checks, while adopting emergent design with string split and AllNonEmpty.

Add a prompt to the pipeline stage that reads input numbers without altering other stages. The demonstration shows incremental changes via an extension method, preserving separation of responsibilities and maintainability.

Extend the pipeline by inserting a new stage that interlaces input number sequences with the desired result using LINQ Zip, within an iterative development workflow.

Organize operations into stages that transform state into a new state, ensure each stage does one task, and compose stages into pipelines to handle complex tasks with fewer defects.

Develop an emergent design algorithm that constructs arithmetic expressions from input numbers through iterative development, creating a flexible solver that lists all possible solutions and prints them to the console.

Explore how to choose names for operations in an object-oriented C# solution, focusing on constraints, exact vs approximate solver behavior, and expressing distinct expressions to reduce ambiguity.

Isolating the outer layer of the algorithm teaches breaking complex problems into subproblems, guiding output formatting with expression objects, handling missing value properties, and applying SelectMany for multiline reports.

Explore onion-like layering of algorithms, building an outer wrapper around an inner sub-algorithm to enable runtime versioning, substitution, and reuse while preserving correctness through interfaces.

Reuse behavior by wrapping production behavior and a demo stage into separate methods to reuse an inner algorithm while preserving the pipeline structure.

Parameterize algorithms to enable reuse by exposing a prompt label in constructors, reducing code duplication with a reusable inputs reader.

Explore emergent algorithm design through a pipeline of stages that perform well-defined transformations. Learn to compose wrapper-around-subordinate algorithms into onion-like, reusable, runtime-replaceable behaviors for complex arithmetic expression generation.

Define the role of a function within emergent design by iteratively building a summing expression using all input numbers, covering one use case at a time.

Watch how an abstract expression emerges as a Literal derives from Expression, overriding Value, enabling to-string debugging, while design iterates with numbers to form expressions.

Order use cases by complexity from flat sums to recursive additive and multiplicative expressions, with precedence, parentheses, and customer rules to keep numbers growing by value.

Iteratively implement the simplest use case by modeling addition as binary left-associative expressions, building a binary tree of add nodes, and leaning on the compiler to guide correct expression design.

Clean up the design after each iteration to remove duplicates and relocate concrete implementations into sub-namespaces. Improve simplicity, maintenance, and extensibility while preserving behavior.

Iteratively design algorithms by linking implementations to use cases, start with simple items, extend to complex ones, and perform cleanup iterations to keep the solution clean for emergent behavior.

Learn iterative development by building a function to split sequences into left or right subsequences, handle the empty sequence special case, and progressively refine with lazy evaluation and refactoring.

Generalize the DistinctFor method to produce additive and subtractive expressions from a sequence of numbers using a split-based partitioning approach, with literals and iterative refactoring guiding the design.

Attach unrelated behaviors to expressions via extension methods, adding Add and Subtract operations while a base BinaryExpression delegates value combination to derived classes, enabling clean toString and debugging work.

Recognize the missing data structure by naming the left and right partitions, refactor Split to return partitions, and introduce a Partition type for LINQ-friendly design.

Refactor by extracting a general Partition class, making it generic over T, and turning numbers into literals. Move infrastructure to a common namespace and simplify the expression stream.

Refactor iteratively to extract classes, move methods, and generalize parameters. The process makes domain-related code clearer and shorter, while generalizing data structures into reusable components.

Augment the algorithm by partitioning literal sequences into all possible subsequences, generating multiplicative expressions, and combining them with addition and subtraction within emergent design, covering all four arithmetic operations.

Fill missing types in C# by introducing the static Partitionings class and a generic Partitionings class that returns all partitionings and constructs expression trees for multiplication.

Develop a general‑purpose, lazy expansion algorithm that endlessly partitions a sequence into all partitionings, enabling reusable, type-agnostic expansion via a queue.

Implement the expand method for the partitioning class to split partitions into two non-empty parts in ascending order, and demonstrate iterative development by building new partitionings from existing ones.

Add division as a non-commutative, left-associative operation to multiplicative expressions through three-way partitioning and a TryDivide design, enabling cross-product generation and recursive expressions via small iterative refinements.

Refactor the expression stream to separate additive and multiplicative passes, apply partitioning, and build all legal expressions while isolating complexity.

Explores the domain model's power to construct and count distinct arithmetic expressions from numbers, generate problems, and produce printable reports.

Develop a deep domain model by applying iterative, emergent object-oriented design that evolves classes, algorithms, and data structures through small, controllable steps.