Loops - Multimedia Introduction to Programming Using Java - page 231

(c) x= 1; i= 2; (d) x= 2; y= 4; z= 1;

while (i <= 7) { while (y != 0) {

x= x * i; if (y%2==0) {

i= i + 2; x= x * x;

} y= y / 2;

} else {
z= z * x;
y= y - 1;

}

}

Answers to self review exercises

SR1. See beginning of Sec. 7.1.1.

SR2. See Sec 7.1.1.

SR3. (a)

x 1 1 2 6
i 1 2 3 4

(b)

x 1 3 6 6
i 3 2 1 0

(c)

x 1 2 8 48
i 2 4 6 8

(d)

x 2 4 16
y 4 2 1 0
z 1 16

7.2 Understanding and developing loops

Loops are far more complicated than assignments or if-statements, and, general-
ly speaking, learning how to develop loops is more difficult than learning about
assignments or if-statements. In this section, we go into detail about how to think
about loop development and how to annotate a loop with comments that help the
reader (and writer) understand it. We start with a discussion of some notation that
helps simplify discussions of some loops.

Style Note
13.2, 13.2.3
indenting
loops

A note on ranges h..k
We often want to say something about a range of integers, for example, the
integers 5 , 6 , 7 , and 8 . To simplify, we use the notation 5..8 to denote this range.
The notation h..k denotes the range of integers h , h+1 , h+2 , …, k-1 , k .
For example, we might say, “the integers 5..8 have been printed”, or, “ x is