Lo-Fi C#: An Introduction to Coding

What tools do you need to develop C# programs?

You’ll need an IDE and the .NET SDK.

What does IDE stand for and what is it’s role in software development?

IDE stands for Integrated Development Environment. It’s the software you’ll use to write your C# code.

What IDE did you choose? Why?

Anything is fine, as long as it supports C#! Popular choices include Visual Studio Community, Visual Studio Code, and JetBrains Rider.

What is the primary role of a programming language in the context of computer programming?

The primary role of a programming language is to act as a bridge between human language and machine language. It allows humans to write instructions in a way that is easier for them to understand and use, which can then be accurately translated into machine language that a computer can execute.

What happens when you run a C# program? Describe that process in simple terms.

When you run a C# program, your code gets compiled (translated) into something the computer can understand, then the computer follows your instructions step by step and shows the results (like printing text or doing math).

What’s the difference between Console.Write() and Console.WriteLine()? When would you use each?

Console.Write() prints text and keeps the cursor on the same line. Console.WriteLine() prints text and moves the cursor to a new line. Use Write() when you want output to continue on the same line, and WriteLine() when you want it to start a new line afterward.

How would you explain what a “program” is to an 8-year-old?

A program is like a list of instructions you give to a computer—kind of like a recipe. The computer follows the steps exactly to do something, like showing a message or solving a puzzle.

Explain the difference between compiled and interpreted programming languages. Describe how C# is both compiled *and interpreted.*

What is a variable, and why do we use them in programming?

A variable is a named storage location in a program that holds a value which can change as the program runs. We use variables to store, update, and reuse data.

Which C# data type would you use for each of the following?

Write a line of code that declares a variable named importantYear and sets it to 1964.

int importantYear = 1964;

What will the following code print? Why?

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string drummer = "Pete Best";
drummer = "Ringo Starr";
Console.WriteLine(drummer);

What happens if you try to store a word (like "hello") in a variable declared as int?

The program will not compile. You can’t assign a value of one data type to a variable of another (incompatible) data type. You also can’t change the data type of a variable after you’ve declared it.

What’s wrong with this variable name: 4ladsFromLiverpool?

A C# variable name can’t start with a number. You could call it fourLadsFromLiverpool instead.

True or False: You must always assign a value to a variable at the same time you declare it

False. You can declare a variable and assign a value to it later:

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int albums;
albums = 12;

What are compound assignment operators in C#? Provide examples of how they are used in arithmetic operations.

Compound assignment operators combine an arithmetic operation with assignment. Examples:

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int numBeatles = 5;
numBeatles -= 1; // Rest in peace, Stuart Sutcliffe!

Write a short program that asks for the user’s name and the number of Beatles albums they own, and then prints a personalized message like: “Hello Stu, you have 5 Beatles albums.”

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Console.Write("What is your name? ");
string name = Console.ReadLine();

Console.Write("How many Beatles albums do you own? ");
int albums = Convert.ToInt32(Console.ReadLine());

Console.WriteLine($"Hello {name}, you have {albums} Beatles albums.");

10. What are the two ways to convert a string to a numeric type, such as int or double? Show the syntax of each.

You can convert a string to a numeric type using either the Convert class or the Parse method. Here are examples of both:

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string nineteenSixtyNine = "1969";
int woodstockYear = Convert.ToInt32(nineteenSixtyNine); // Using Convert class
woodstockYear = int.Parse(nineteenSixtyNine); // Using Parse method

What is a method, and why would you use one in your code?

A method is a named block of code that does something — like a mini-program inside your program. You use methods to organize your code, avoid repetition, and make your program easier to understand and manage. (Like reusable LEGO chunks.)

What’s the difference between calling a method and defining a method?

Defining a method is writing what the method does. Calling a method is telling it to actually run. You define once, but can call it as many times as you want.

What does the keyword void mean in a method definition?

void means the method doesn’t return anything. It just does something, like printing text, but doesn’t give a value back.

Consider the code below. a. What does it do? b. How would you call it to greet someone named "Brian Epstein"?

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static void Greet(string name)
{
    Console.WriteLine($"Hello, {name}!");
}

Consider the code below. a. What would the method return? b. How would you use that returned value?

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static int AddTwoNumbers(int a, int b)
{
    return a + b;
}

Consider the code below. a. Overload the method by accepting the name of a band to introduce. b. Demonstrate how to call each version of the method.

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static void AnnounceBand()
{
    Console.WriteLine("Ladies and gentlemen, The Beatles!");
}

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What are the two main parts of a test case, and why is it important to define them before you start writing code?

A test case includes inputs (the data the program uses) and the expected output (the result the program should produce). Defining test cases before coding helps you understand the problem better and plan how your program will work, instead of just jumping in and hoping it all comes together.

Why is it not enough to test your program with just one set of inputs? Give an example of an “edge case” that might catch a bug.

One test case might only show that your code works in that specific situation. To be sure your program works in general, you need to test it with a variety of inputs, including unusual or tricky ones.

How can writing your test cases early help you figure out what variables or calculations your program will need?

Thinking through test cases makes you figure out the steps to solve the problem. It helps you see what data you need, what formulas you’ll use, and what your program should do at each stage. It’s like using the test cases to reverse-engineer your program before you even start coding.