Objective-C Fundamentals

24 CHAPTER 1 Building your first iOS application
Figure 1.13 Setting a breakpoint to break into the debugger whenever the first line of the simulateCoinToss:
method is called. Notice the arrow in the margin indicating an active breakpoint.
For the Coin Toss game, let’s add a breakpoint to the start of the simulateCoinToss:
method. Open the CoinTossViewController.m file and scroll down to the source code
implementing the simulateCoinToss: method. If you then click the left margin
beside the first line, you should see a little blue arrow appear, as shown in figure 1.13.
The blue arrow indicates that this line has an enabled breakpoint. If you click the
breakpoint, it becomes a lighter shade of blue, indicating a disabled breakpoint, which
causes the debugger to ignore it until it’s clicked again to re-enable it. To permanently
remove a breakpoint, click and drag the breakpoint away from the margin. Releasing
the mouse will show a little “poof” animation, and the breakpoint will be removed.
1.6.3 Running the CoinToss game in the iPhone simulator
With the breakpoint in place, you’re finally ready to run the application and see it in
action. Select Run from the Product menu (Cmd-R). After a few seconds, the application