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Unformatted text preview: the flowchart of Figure 11.5 is
incomplete because the process loop has introduced a new problem. The process loop
shown does not have a logical ending. It will continue to attempt to repeat those four
steps until someone manually cancels the job. This is an example of an infinite loop and
hence the flowchart of Figure 11.5 does not represent an algorithm because an algorithm
must terminate. So we have to find out a way of terminating the algorithm. This is done
by the use of a decision symbol.
Figure 11.6 shows a flowchart, which uses a decision step to terminate the algorithm. In
this flowchart, another variable Count has been introduced which is initialized to zero
outside the process loop and is incremented by 1 after processing the data for each
student. Thus, the value of Count will always be equal to the number of students whose
data has already been processed. At the decision step, the value of Count is compared
with 50, which is the total number of students who have appeared for the examination.
The steps within the process loop are repeated until the value of Count becomes equal to 50, the instruction at the decision step causes the control to flow out of the loop and the
processing stops because a terminal symbol labeled Stop is encountered. Thus, the
flowchart of Figure 11.6 is a complete and correct solution to the problem of Example
11.4.
Although the flowchart of Figure 11.6 is a correct solution to the given problem, it suffers
from two major drawbacks. The first drawback is that in order to make the decision at the
decision step, one must know the exact number of students who appeared in the
examination. Suppose the examination of Example 11.3 is a university examination in
which the total number of students who appeared for the examination is too large (say
more than ten thousand). In such a situation, the counting of the total number of input
records (data for each student) becomes a tedious job. Even then, if we do stick on
counting the input records manually and supply the number of records to be compared
against Count in the decision box and suppose while...
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This document was uploaded on 04/07/2014.
 Spring '14

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