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Limitations of the Case Control Structure

19 一月, 2016 - 11:41

Most programming languages, including C++, do not allow ranges of values for case like structures. Consider this flowcharting example that used ranges:

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Figure 12.2 Flowcharting example using ranges

Consider also the following pseudocode for the same logic:

Case of age  0 to 17     Display "You can't vote."  18 to 64    Display "You're in your working years."  65 +        Display "You should be retired."Endcase

Using the case control structure when using non integer family or ranges of values is allowed when designing a program and documenting that design with pseudocode or fowcharting. However, the implementation in most languages would follow a nested if then else approach with complex Boolean expressions. The logic of the above examples would look like this:

if age  >  0 and age <= to 17  display You can't vote.else  if age is >= 18 and age <= 64  display You're in your working years.else  display You should be retired.