Consider the following program written in C syntax:
void swap(int a, int b) {
int temp;
temp = a;
a = b;
b = temp;
} void main() { int value = 2, list[5] = {1, 3, 5, 7, 9};
swap(value, list[0]);
swap(list[0], list[1]);
swap(value, list[value]);
}
For each of the following parameter-passing methods, what are all of the
values of the variables value and list after each of the three calls to
swap?
1. Passed by value
2. Passed by reference
3. Passed by value-result
6.

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MrRoyal MrRoyal · Answer 1 · 2022-04-21T18:57:43+02:00

The values of the variables value and list after each of the three calls to

swap are:

1. Passed by value

In this case, the values of the actual arguments remain unchanged; So the variable value and the list would retain their initial values

The end result is:

value = 2 and list[5] = {1, 3, 5, 7, 9};

2. Passed by reference

With pass by reference, the arguments are changed.

Given that

value = 2 and list[5] = {1, 3, 5, 7, 9};

The value of variable value is swapped with list[0].

So, we have:

value = 1 and list[5] = {2, 3, 5, 7, 9};

Then list[0] and list[1] are swapped

So, we have:

value = 1 and list[5] = {3, 2, 5, 7, 9};

Lastly, value and list[value] are swapped

So, we have:

value = 2 and list[5] = {3, 1, 5, 7, 9};

The end result is:

value = 2 and list[5] = {3, 1, 5, 7, 9};

3. Passed by value-result

Since there is no loop in the program, the pass by value-result has the same output as the pass by reference.

So, the end result is:

value = 2 and list[5] = {3, 1, 5, 7, 9};