13. C# (Project A : The Method Calculator)

Source: Dev.to

Overview

A small project designed to enforce proper method design in C#.
The focus is on structure, not on complex mathematics.

Requirements

1. No logic inside Main – all responsibilities must be separated.
2. Input – ask the user for two numbers using Console.ReadLine() and convert them with int.Parse().
3. Operation selection – prompt the user to choose an operation (e.g., Add, Subtract, Get Remainder).
4. Method dispatch – use an if (or switch) statement to call the appropriate method based on the user’s choice.

Expected flow

Method Specifications

Each calculation method must:

• Accept two integers as parameters.
• Return an integer result.
• Never print anything; all output is handled in Main.

int Add(int a, int b) { /* ... */ }
int Subtract(int a, int b) { /* ... */ }
int GetRemainder(int a, int b) { /* ... */ }

Guidelines

• Use int.Parse for converting string input to integers.
• Employ the modulo operator (%) for the remainder calculation.
• Keep processing and output separate: Main should only handle user interaction and display results.
• Do not duplicate calculation logic inside Main.
• Do not hard‑code numbers or collapse everything into a single method.

Learning Objectives

• Think in terms of responsibilities and separation of concerns.
• Practice using parameters and return values correctly.
• Experience the benefits of refactoring and understanding why separation matters.
• Build a foundation for basic program architecture and method design.

If you encounter difficulties, that struggle is the intended part of the exercise—use it to deepen your understanding of clean code structure.