Question

The valid range of values for integer variable x is described by this relational expression: -10<=x && x<=10. Which of the following integer values could be used as a sentinel value when inputting a value for x in a loop?

a) -10 to 10
b) 0 to 20
c) -20 to 0
d) -15 to 15

Answer 1

The appropriate range for a sentinel value outside the -10 to 10 range is c) -20 to 0, as it provides values that do not overlap with the valid values for the integer variable x. The correct answer is c) -20 to 0.

Step-by-step explanation:

When choosing a sentinel value for an integer variable x where the valid range of values for x is described by the relational expression -10≤x && x≤10, this sentinel value should be outside the valid range to be effective in the loop control.

For example, if x represents a specific integer between -10 and 10 inclusive in a program, a sentinel value should be an integer not within this range.

In the provided options, the only range that includes appropriate sentinel values is c) -20 to 0, as all values in this range are less than the minimum valid value of -10 for x.

It should be noted that while any number from -20 to -11 could serve as a sentinel value, zero cannot since it falls within the valid range for x.