Sams Teach Yourself Xcode® 4 in 24 Hours

Hour 19. Getting the Bugs Out

What You’ll Learn in This Hour:

• How to use the debugger to find out why your program crashed

• How to use the debugger to find out how your program is working

• How to manipulate your running program to test ideas and potential fixes for problems

In the preceding hour, you learned about using unit tests, which are a great tool for validating that everything is still working right when it’s working right. However, they are only so helpful when something is working wrong. When your code is not behaving as planned, you need to be able to dig into it and check the values that variables are holding and verify that execution is following the path through your code that you were planning.

So far in this book, we have ...