All language subtitles for 010 Debugging Functions_en

A lot of the times your function is not going to return the correct value.

So in this lesson, you're going to learn to debug functions by using breakpoints.

Once again, the code you're going to open isn't going to behave the way that you want it to.

So I'll give you a few seconds to pause and read this description.

And now, based on the description you just read, the starter code should place Gryffindor in first

place, but if we actually run it.

They are in fourth.

Something is wrong and using breakpoints, we can visualize the runtime.

OK, well, there's the first mistake, Gryffindor won by 400 points, but the points margin indicates

that they lost by 400.

We need to reverse the operation and this is a very common type of accidental mistake that you can easily

identify when you visualize the runtime.

So let's launch another debugging session.

And the final up, but it's three, but since Gryffindor is ahead by more than 300 points, they should

be in first place to find out what's going on.

We need to step into the function.

When a breakpoint hits the function call, you can step into it.

So restart the debugging session.

Once the breakpoint hits the function, you can step into its.

And after you step into the function, it evaluates the first condition.

For us, the second one.

True.

And they return three.

It stores the return value in the variable ranking.

Which we then printed.

So we need to rearrange the conditions to go from highest to lowest.

All right, now it returns the correct results.

Now we're going to run some test cases and use break points to visualize each runtime will change.

Gryffindor points to eight fifty rather than clode to five hundred.

That should put Gryffindor in first, let's try it out.

OK, good.

Now we'll do 620 and 500 should put them in second.

OK, great.

We'll do 450 and 500, I should put them in third.

Nice.

Then we'll do a hundred and five hundred and I should put them in last.

And indeed, it does.

Now, if you want to explore the hidden world of Java, you can step into built in functions.

I can step into print line.

And this is the code that runs behind the scenes to print your code.

I can step into that random.

Interesting, it returns the next double that the random number generator produces, OK, makes sense.

I can step into math that, Max.

And this syntax is very interesting.

It's called conditional assignment, and I made you use it in the last exercise.

Basically, it checks if value A is greater than or equal to be.

If it's true, Gever returns the value that follows the questionmark.

Otherwise, Javor returns the value that follows the colon.

B. In this case, the condition is false.

So it's going to return B.

All right, one more thing, notice that Java documents every function.

This function takes two parameters and returns the larger of Perram, A and B, very similar to how

we do things pretty cool.

All right, we used breakpoints to debug a function.

You visualized how a function runs by stepping into it, and if you're curious about built in functions,

you can step into those as well.