Transcript Chapter 1

Chapter 7
LOOPING OPERATIONS:
ITERATION
Chapter 7
• The Flow of the while Loop
false
test
while
expression
true
loop body
. . .
Chapter 7
• while Loop Syntax
while (test expression)
{
statement 1;
statement 2;
•
statement n;
} //END WHILE
Chapter 7
• DebuggingTip
Remember, an infinite loop is the result of a
logical error in your program. The compiler
will not detect an infinite loop condition.
For this reason, you should always deskcheck your loop structures very closely
prior to coding and execution. A little time
desk-checking will save you a lot of time at
the keyboard.
Chapter 7
• The Flow of the do/while Loop
loop body
do
while
true
test
test
expression
false
. . .
Chapter 7
• do/while Loop Syntax
do
{
statement 1;
•
statement n;
} //END DO/WHILE
while (test expression);
Chapter 7
• The Flow of the
for Loop
for
initialize
counter value
test
. . .
expression on
counter
true
loop body
increment/decrement
counter
false
. . .
Chapter 7
• for Loop Syntax
for (int counter = initial value; counter test;
increment or decrement
counter)
{
statement 1;
statement 2;
•
statement n;
} //END FOR
Chapter 7
• Tips
– Never change the for loop counter within the
body of the loop.
– Do not place a semicolon at the end of the first
line of the for statement unless you purposely
want to create a time delay.
Chapter 7
• The continue Statement
When a continue statement is executed
within a loop, only the current iteration is
terminated and loop execution “continues”
to the next iteration.
Chapter 7
• The break Statement
When a break statement is executed within
a loop, the loop “breaks” and all loop
iterations are terminated. Execution then
passes to the next sequential statement after
the loop.
Chapter 7


Use while whenever there is a possibility
that the loop statements will not need to be
executed.
Use do/while when the loop statements
must be executed at least once.
• Use for when it can be predetermined
exactly how many times the loop statements
must be executed.