Infinite for Loop

1
Infinite for Loop

• If you omit the test condition, the value is
  assumed to be TRUE so the loop will continue
  indefinitely unless you provide some other means
  of exiting.

2
Example 18

• includeltiostream.hgt
• int main()
• double value 0.0
• double sum 0.0
• int i 0
• char indicator 'n'
• for()
• cout ltltendl
• ltlt"Enter a value"
• cingtgtvalue
• i
• sum value
• cout ltltendl
• ltlt"Do you want to enter another value (enter n
  to end)?"
• cingtgtindicator
• if ((indicator 'n') (indicator 'N'))
• break

3
Continue Statement

• Executing continue within a loop starts the next
  loop iteration immediately, skipping over any
  statements remaining in the current iteration.

4
Example19

• includeltiostream.hgt
• int main()
• int i0, value0,product1
• for (i1 ilt10 i)
• cout ltlt"Enter value " ltlti ltltendl
• cout ltlt"\t\t" ltlti ltlt" number is "
• cingtgtvalue
• if (value 0)
• continue
• product value
• cout ltltendl
• cout ltlt"Product (ignoring zero)" ltltproduct
  ltltendl
• ltltendl
• return 0

5
The while Loop

• A while loop causes the program to repeat a
  sequence of statements as long as the starting
  condition remains true.
• The general form of the while loop is
• while (condition)
• statement

6
Example 20

• includeltiostream.hgt
• int main()
• double value 0.0, sum0.0
• int i0
• char indicator 'y'
• while (indicator 'y')
• cout ltlt endl ltlt"Enter a value"
• cin gtgt value
• i
• sum value
• cout ltltendl ltlt"Do you want to enter another
  value (enter y for yes or n to end)?"
• cin gtgt indicator
• cout ltltendl ltlt"The average of the " ltlt i
• ltlt " value you entered is " ltltsum/i ltlt"."
  ltltendl
• return 0

7
Exercise

• Write a program that asks the user to enter a two
  digit grade (such as 80 or 75) and then display
  the corresponding single digit grade (such as 2
  or 3). Use the following grade ranges
• 90 - 100 4 60 - 69 1
• 80 - 89 3 59 and less 0
• 70 - 79 2

8
Exercise

• Write a program which reads number from cin, and
  adds them, stopping when 0 has been entered.
  Construct two versions of this program, using for
  and while loop.