Introduction to Algorithms

Vaibhav • September 11, 2025

Every program you write is a solution to a problem. But how do you go from a problem to a working program? The answer lies in algorithms. In this article, we’ll introduce the concept of algorithms, explore how to think step-by-step like a programmer, and use real-world analogies to make the idea intuitive. You’ll also get a gentle introduction to flowcharts and pseudocode-two tools that help you plan before you code.

What is an Algorithm?

An algorithm is a step-by-step set of instructions for solving a problem or performing a task. It’s not specific to programming-algorithms exist in cooking recipes, driving directions, and even your morning routine.

In programming, an algorithm is the logic behind your code. It’s the plan you follow to get from input to output. Before you write a single line of C#, you should be able to describe your algorithm in plain language.

You can think of an algorithm as a recipe. The ingredients are your inputs, the steps are your logic, and the final dish is your output.

Thinking Step-by-Step

Computers are fast, but they’re not smart. They need clear, unambiguous instructions. That’s why algorithmic thinking is so important. It forces you to break down a problem into small, logical steps that a computer can follow.

Let’s say you want to write a program that greets the user. Here’s how you might think about it: 

1. Ask the user for their name
2. Wait for the user to type their name
3. Store the name
4. Display a greeting using the name

That’s an algorithm. It’s not code yet-but it’s a clear plan. Once you have this plan, turning it into C# is much easier.

Real-World Analogy: Making Tea

To make the idea of algorithms more relatable, let’s look at a real-world example: making a cup of tea. Here’s the algorithm: 

1. Boil water
2. Place a tea bag in a cup
3. Pour hot water into the cup
4. Wait for 3 minutes
5. Remove the tea bag
6. Add sugar or milk if desired
7. Stir and serve

This is a perfect example of an algorithm. It’s a sequence of steps that leads to a result. If you skip a step or do them out of order, the result won’t be what you expect.

Programming works the same way. The computer follows your instructions exactly. If your algorithm is wrong, your program will be too-even if the code is technically correct.

The word “algorithm” comes from the name of a 9th-century Persian mathematician, Al-Khwarizmi. His work laid the foundation for modern algebra and computation.

Visualizing Algorithms with Flowcharts

Sometimes it helps to draw your algorithm before you write it. A flowchart is a diagram that shows the steps of an algorithm using shapes and arrows.

Here’s a simple flowchart for greeting a user: 

[Start]
   ↓
[Ask for name]
   ↓
[Read input]
   ↓
[Display greeting]
   ↓
  [End]

Each box represents a step. The arrows show the flow of control. Flowcharts are great for planning and for explaining your logic to others.

You don’t need special software to draw flowcharts. A pen and paper work just fine. The goal is to clarify your thinking, not to make it pretty.

Writing Algorithms in Pseudocode

Another way to plan your algorithm is with pseudocode. Pseudocode is a mix of plain English and programming-like structure. It’s not real code, but it’s close enough to help you transition into writing actual C#.

Here’s the greeting algorithm in pseudocode: 

START
  DISPLAY "What is your name?"
  READ name
  DISPLAY "Hello, " + name + "!"
END

This is easy to read and easy to translate into C#. You don’t have to worry about syntax or semicolons-just focus on the logic.

Later, when you write the real code, it might look like this: 

Console.Write("What is your name? ");
string name = Console.ReadLine();
Console.WriteLine("Hello, " + name + "!");

See how the pseudocode maps directly to the actual code? That’s the power of planning.

Why Algorithms Matter

You might be wondering: why not just start coding? Why bother with algorithms, flowcharts, or pseudocode?

Here’s why:

  • Algorithms help you think clearly before you write code
  • They reduce bugs by forcing you to plan
  • They make your code easier to understand and explain
  • They help you break big problems into smaller, manageable steps

As your programs get more complex, having a solid algorithm becomes even more important. It’s the difference between hacking something together and building something that lasts.

Before you write any code, write down the steps your program needs to follow. Use plain language, flowcharts, or pseudocode-whatever helps you think clearly.

Practicing Algorithmic Thinking

Let’s try another example. Suppose you want to write a program that asks the user for their name and age, then prints a message.

Here’s the algorithm: 

1. Ask for the user's name
2. Read the name
3. Ask for the user's age
4. Read the age
5. Display a message using both name and age

In pseudocode: 

START
  DISPLAY "What is your name?"
  READ name
  DISPLAY "How old are you?"
  READ age
  DISPLAY "Hello, " + name + ". You are " + age + " years old."
END

And in C#: 

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

Console.Write("How old are you? ");
string age = Console.ReadLine();

Console.WriteLine("Hello, " + name + ". You are " + age + " years old.");

Notice how the algorithm, pseudocode, and real code all follow the same structure. That’s the goal: to make the transition from idea to implementation as smooth as possible.

Summary

In this article, you learned what algorithms are and why they matter. You now understand:

  • How to think step-by-step like a programmer
  • How to use real-world analogies (like making tea) to understand algorithms
  • How to visualize logic using flowcharts
  • How to plan your code using pseudocode
  • How algorithms help you write better, clearer, and more reliable programs

Algorithms are the foundation of programming. In the next article, we’ll build on this by introducing a simple problem-solving methodology that you can apply to any coding challenge.