Question

Which xxx and yyy correctly swap a and b?

1) xxx a = b; yyy b = a;
2) xxx a = b; yyy b = tmp;
3) xxx a = b; yyy a = tmp;
4) xxx a = b; yyy a = b;

Answer 1

The correct way to swap the values of a and b is xxx a = b; yyy a = tmp.

Step-by-step explanation:

The option (3) xxx a = b; yyy a = tmp; is the correct way to swap the values of a and b.

When we have xxx a = b, it assigns the value of b to a. In yyy a = tmp, we assign the value of tmp to a. Therefore, the value of b is stored in a temporarily and then assigned back to b.

For example, if a = 3 and b = 5, after executing xxx a = b, a becomes 5. Then, executing yyy a = tmp, a is assigned the value of tmp which is 3. Now, both a and b have been swapped correctly.