Question

C++ code... Need help asap

QUESTION 2 (20 MARKS) The following program shows a simple example to calculate average of three marks. Explain how the program is working as well as data management in your memory. You can illustrates this by using table or drawing. The sample output is illustrated in Figure Q2. 1 #include <iostream> 2 using namespace std 3 float calculateAverage (int* marks) int sum=0; float average, for (int İzd ;ia;i++) sumesum+( (marks+i)12 10 11 average float (sum) /3: 12 13 1 14 void displayAverage (tloat avg) 15 1 16cout<c avgccandia 17 1 18 int main ) 19 I 20 21 return averager int marks 13) (88,42,73) tloat avg 23 avg calculateaverage (marks) a 24 25 displayàverage Iptzavgi a retuen 0 ClUsers FKP Desktop Sem 1 2018-2019 Test 1ibin DebugiSem 1 2018-2019 Test 1.exe 67.6667 Process returned θ (6x0) execution time : θ.e62 s Press any key to continue. Figure Q2

Answer 1

Your Code:
#include<iostream>
using namespace std;
float calculateAverage(int *marks)
{
int sum =0;
float average;
for(int i=0; i<3; i++)

{
sum = sum + (*(marks+i));
}
average = float(sum)/3;
return average;
}
void displayAverage(float *avg)
{
cout<<*avg<<endl;
}
int main()
{
int marks[3]={88,42,73};
float avg;
float *ptrAvg = &avg;
avg = calculateAverage(marks);
displayAverage(ptrAvg);
return 0;
}

The code flow is as follows
The execution starts from main function
The first line in main function denotes an array marks with 3 elements
Then we declare avg as float
The next line float *ptrAvg = &avg; assigns the address of the variable avg to the pointer ptrAvg. This can be also said as a pointer variable ptrAvg points to the address of avg
Now we have the address of avg in *ptrAvg.
Then next call the function calculateAverage(marks). This call the function calculateAverage with an argument marks.
The program flow changes to the function calculateAverage. Now lets see what happens in that function
It reads the argument as pointer. that means *marks is a pointer which points towards the array marks[] which we have declared in the main function. Now we can access the array directly. Which means in this function we are using the original array instead of copy.
Inside the for loop, we are adding the marks
the statement sum = sum + (*(marks+i)); , Indicates as follows,
*(marks+i) it point towards the ith index of the array which is pointed, each time.and take the value in that index.
Next we calculate the average and return it.
Now we are back in our main function which next calls displayAverage function with ptrAvg, The ptrAvg is actually pointing towards the address of avg. The value returned from calculateAverage is avg.
Now flow changes to displayAverage
it prints the value in the adress denoted as *avg.
This is the basic flow of the program.

Now coming to memory management, we have mainly 3 widely used variables
marks
avg
ptrAvg
It can be illustrated as

オmaors さn

Hope this is helpful

please comment if you have any doubts