How do I add this part: Keep a running total of the valid inflation rates and the number of computed rates to calculate average

Question

#include <iostream>
using namespace std;

double inflationRate (float old_cpi, float new_cpi);

int main()
{
float old_cpi, new_cpi;
char again;

do
{
cout << "Enter the old and new consumer price indices: ";
cin >> old_cpi >> new_cpi;

cout << "Inflation rate is " << inflationRate(new_cpi, old_cpi) << endl;

cout << "Try again? (y or Y): ";
cin >> again;

} while((again == 'Y') || (again == 'y'));

return 0;
}

double inflationRate(float old_cpi, float new_cpi)
{
return ((old_cpi - new_cpi) / new_cpi * 100);
}

Answer 1

You can use a vector of doubles to store your inflation rates.

Before asking for continuation, you can just push the last valid inflation rate inside the vector.

Then run a for loop like this:

double avg=0;
for(auto v:vec) avg+=v;
avg/=vec.size();

This will store the average of the vector named vec, inside avg.

Or you can just keep a variable avg, and add your inflation rate directly to it in the do...while loop. At the same time, keep incrementing a counter variable to keep note of the size, and in the end, divide avg by the counter variable to get the average.

Answer 2

Here, try this : https://code.sololearn.com/c9BX9YiNRLxd/?ref=app

Your code has some errors, like you didn't define any variable named inflationRate. So you must call the function again when assigning to sum. And I think the average must be the sum divided by number of occurrences, which you must count using a counter variable for this case.

Answer 3

This is what I did so far: (average does not work)
#include <iostream>
using namespace std;

double inflationRate (float old_cpi, float new_cpi);

int main()
{
float old_cpi, new_cpi;
double sum, average;

cout << "Enter the old and new consumer price indices: ";
cin >> old_cpi >> new_cpi;

cout << "Inflation rate is " << inflationRate(old_cpi, new_cpi) << endl;

sum += inflationRate;

average = sum/inflationRtae;

cout << average << endl;

return 0;
}

double inflationRate(float old_cpi, float new_cpi)
{
return ((new_cpi - old_cpi) / old_cpi * 100);
}