Chapter 5.5, Problem 5.24CP

Explanation of Solution

Sentinel:

Sentinel is the special value which is used to stop the sequence of series when there is no indication of explicit size.

• It is also called as “flag value” or “dummy value” created in the algorithm to terminate the program.
• The sentinel value must be a distinct value from the other data values, so that it is guaranteed to end the data.
  • For example: “null character” is used to end the null terminated string and a “negative integer” is used to indicate the end of sequence for non-negative integers.
• Whenever the program reads the sentinel value it stops the execution of loop, because it knows that it reaches the end of sequence.

Example Program:

The following program code uses the sentinel value:

#Initialize the variables

total = 0

counter = 0

# Get the marks

...