Controlling the Flow of Your Program - Beginning Java Programming: The Object-Oriented Approach - page 156

12. One final line will be output to the console indicating the end of the program.
13. If you executed the for loops in the other Try It Out exercises in this chapter, you'll notice that
they all produce the same output. For these simple examples, the loops can be used somewhat
interchangeably, with some small adaptations. You will encounter situations in the later chapters
that are more suited to one type of loop over others.

comparing for and while loops
As you've seen through the examples and exercises in the previous sections, for and while loops
can both be used to obtain the same outcome. So how do you know which one to use?

For some problems, this will simply be a matter of preference. Some programmers tend to use for
loops, except when a situation really demands a while loop. Others prefer while loops and include
for loops only when needed. Many programmers, through practice and experience, learn a certain
feeling for which one is best suited for the problem at hand, and you will too.

In general, keep in mind the following points:

➤

If you are iterating over a collection, consider a for loop first.

➤

If you know the number of loops in advance, consider a for loop first.

➤

If you don't know the number of iterations, but the number will depend on a certain condi-
tion, consider a while loop first.

When making your decision, simplicity and clarity are important considerations. You want a solu-
tion that's the simplest to code, for your own sake, and clearest to read and understand, for yourself
and others who will have to maintain or reuse your code later.

creating switches
Earlier in this chapter, you learned that if-then statements are one of the basic control structures.
Now you will see switch statements, which function in a similar way to if-then statements, but with
a different syntax. They are particularly useful when you have several else clauses. A switch state-
ment evaluates a single variable and, depending on its value, executes a certain block of code. The
general syntax of a basic switch statement is as follows:

switch (/*variable*/ {
case 1: /*execute these statements*/; break;
case 2: /*execute these statements*/; break;
default: /*execute these statements*/;
}

The variable that's evaluated can be a primitive byte , short , char , or int , as well as enumerated
types and String . The switch checks the value of the variable for a match in one of the cases. If
they are equal, the statements in that case will be executed.