## Chapter 5. Program Looping

In Objective-C, you can repeatedly execute a sequence of code in several ways. These looping capabilities are the subject of this chapter, and they consist of the following:

The `for`

statement

The `while`

statement

The `do`

statement

We start with a simple example: counting numbers.

If you were to arrange 15 marbles into the shape of a triangle, you would end up with an arrangement that might look something like Figure 5.1.

**Figure 5.1. Triangle arrangement example**

The first row of the triangle contains one marble, the second row contains two marbles, and so on. In general, the number of marbles required to form a triangle ...