Question

Assume that the variables alpha and omega are each initialized. Which of the following code segments can be used to interchange the values of alpha and omega using the temporary variable temp? For example, if alpha = "race" and omega = "car", the result would be alpha = "car" and omega = "race"

I.temp = alpha;
alpha = omega;
omega = temp;

II.temp = alpha;
alpha = omega;
omega = alpha;

III.temp = omega;
omega = alpha;
alpha = temp;

(A) I and II only
(B) I and III only
(C) II and III only
(D) I, II, and III

Answer 1

To interchange the values of variables using a temporary variable, correct code segments must store the initial value before overwriting. Code Segments I and III correctly swap the values of alpha and omega, while Code Segment II does not. The correct answer to which code segments can interchange the values of alpha and omega is Code Segments I and III only, which corresponds to option (B) I and III only.

Step-by-step explanation:

To determine which code segments can be used to interchange the values of two variables using a temporary variable, we must carefully analyze each given code segment:

• Code Segment I:

temp = alpha;
alpha = omega;
omega = temp;

• Here, the temporary variable temp holds the value of alpha, then alpha is given the value of omega, and finally, the initial value of alpha (stored in temp) is assigned to omega. This successfully swaps the values, so this segment works correctly.

• Code Segment II:

temp = alpha;
alpha = omega;
omega = alpha;

• In this sequence, after alpha is given the value of omega, the line omega = alpha attempts to assign the value of alpha (which is now the original value of omega) back to omega, which would make both variables have the same value, and thus it does not swap the values correctly.

• Code Segment III:

temp = omega;
omega = alpha;
alpha = temp;

• The process here is similar to Code Segment I, but temp holds the original value of omega this time. The end result is the same: alpha and omega have effectively swapped their values.

The correct answer to which code segments can interchange the values of alpha and omega is Code Segments I and III only, which corresponds to option (B) I and III only.