Activate/deactivate breakpoints button in Xcode is a blue button that appears in the Debug Area, which is typically located at the bottom of the Xcode interface. This button is used to add or remove breakpoints in your code.

Breakpoints are a powerful debugging tool that allow you to pause the execution of your code at a specific line or function, so that you can investigate the state of your app or the values of your variables. By setting a breakpoint, you can stop your code at a specific point in its execution and examine its behavior.

Example

In this example, we have an array fruits containing three elements: 'apple', 'banana', and 'orange'.

We want to remove the last element of the array repeatedly within a loop. However, a potential issue could arise if we attempt to remove more elements than are currently in the array, causing a runtime error.

We've set a breakpoint inside the loop, specifically on the fruits.removeLast() line.

By placing a breakpoint inside the loop at the fruits.removeLast() line, we can step through the code and inspect the state of the fruits array at each iteration.

This allows us to identify the issue if and when it occurs. When the loop reaches the point where there are no more elements to remove, the debugger will pause the execution, and you can examine the array to understand the problem.

This helps you find and fix the issue, ensuring that your code doesn't crash due to an invalid operation.