Big Java, 4th Edition

Chapter 6. Iteration

CHAPTER GOALS

• To be able to program loops with the while and for statements

• To avoid infinite loops and off-by-one errors

• To be able to use common loop algorithms

• To understand nested loops

• To implement simulations

  T To learn about the debugger

This chapter presents the various iteration constructs of the Java language. These constructs execute one or more statements repeatedly until a goal is reached. You will see how the techniques that you learn in this chapter can be applied to the processing of input data and the programming of simulations.

while Loops

In this chapter you will learn how to write programs that repeatedly execute one or more statements. We will illustrate these concepts by looking at typical investment situations. Consider a bank account with an initial balance of $10,000 that earns 5 percent interest. The interest is computed at the end of every year on the current balance and then deposited into the bank account. For example, after the first year, the account has earned $500 (5 percent of $10,000) of interest. The interest gets added to the bank account. Next year, the interest is $525 (5 percent of $10,500), and the balance is $11,025.

How many years does it take for the balance to reach $20,000? Of course, it won't take longer than 20 years, because at least $500 is added to the bank account each year. But it will take less than 20 years, because interest is computed on increasingly larger balances. To know the exact answer, we will write a program ...