Give the values that are changed after the call to the swap function if the parameter passingmechanism used is call-by-reference.swap ( i , a [ i ] )Assume the initial value of i. Make any other necessary assumptions. Justify your answerby showing the values at each step of the swap function.
Question
Give the values that are changed after the call to the swap function if the parameter passingmechanism used is call-by-reference.swap ( i , a [ i ] )Assume the initial value of i. Make any other necessary assumptions. Justify your answerby showing the values at each step of the swap function.
Solution
In order to answer this question, we first need to understand what call-by-reference means. In call-by-reference, the function gets a reference to the actual variables passed in, not a copy of their values. This means that if the function changes the values of those variables, the changes are reflected in the original variables outside the function.
Let's assume that the swap function is defined as follows:
void swap(int &x, int &y) {
int temp = x;
x = y;
y = temp;
}
This function swaps the values of the two variables passed to it.
Now, let's assume that i is an integer variable and a is an array of integers. Let's also assume that initially i = 2 and a = [1, 2, 3, 4, 5].
When we call swap(i, a[i]), we're passing i and a[i] (which is a[2] or 3) to the swap function.
Here's what happens step by step:
-
Inside the swap function,
xis a reference toiandyis a reference toa[i]. Sox = 2andy = 3. -
tempis assigned the value ofx, sotemp = 2. -
xis assigned the value ofy, so nowx = 3. Sincexis a reference toi,ialso changes to3. -
yis assigned the value oftemp, so nowy = 2. Sinceyis a reference toa[i](which is nowa[3]becauseihas changed),a[3]changes to2.
So, after the call to the swap function, i = 3 and a = [1, 2, 2, 4, 5].
Similar Questions
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