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Understanding AI Output: What's Really Happening

After your first few interactions with an AI coding assistant, you have some code. But what does it actually mean? This post will teach you how to read the code AI generates, a crucial skill for any developer.

Reading Code Line-by-Line​

Code is a set of instructions for the computer. Let's break down the number guessing game from our previous post.

// A simple number guessing game
const targetNumber = Math.floor(Math.random() * 100) + 1;
let guess = 0;

while (guess !== targetNumber) {
  guess = parseInt(prompt("Guess a number between 1 and 100:"));

  if (guess > targetNumber) {
    alert("Too high!");
  } else if (guess < targetNumber) {
    alert("Too low!");
  }
}

alert("You got it! The number was " + targetNumber);
  • const targetNumber = ...: This declares a constant variable named targetNumber and assigns it a random number between 1 and 100.
  • let guess = 0;: This declares a variable named guess that we can change later.
  • while (guess !== targetNumber): This is a loop. It will keep running the code inside the {} as long as the guess is not equal (!==) to the targetNumber.
  • guess = parseInt(...): This line gets input from the user, converts it to a number, and updates the guess variable.
  • if...else if...: This is a conditional statement. It checks if the guess is too high or too low and provides feedback.
  • alert(...): This displays a message to the user.

The "Explain This Code" Prompt​

If you ever feel lost, your AI is there to help. A powerful technique is to paste the code back to the AI and ask:

"Explain this code to me in simple terms, line by line. I am a complete beginner."

This helps you build your understanding and ensures you're not just blindly copying and pasting.

When to Trust AI vs. When to Verify​

Think of your AI as a talented but sometimes forgetful junior developer.

  • Trust for: Boilerplate code, syntax, common algorithms.
  • Verify for: Complex logic, dates and times, security-sensitive code, or anything that seems too complex or magical.

Always run the code and test it yourself.

Common Beginner Confusions​

  • Syntax vs. Logic: Syntax is the grammar of the code (like a missing comma). Logic is the meaning and flow (like checking if a number is greater than instead of less than). AI is great at fixing syntax errors, but you need to check the logic.
  • The "Why": The AI gives you the "what" (the code), but you need to understand the "why." Always ask yourself, "Why is this line of code here?"

Your Turn: Annotate the Code​

Take the number guessing game code above. Copy it into a text file and, for each line, write a comment explaining what it does in your own words. This is a fantastic way to solidify your understanding.