calculate sum and avg of the numbers in data file - c++

Question

created a data file to store integers and after the program reads the numbers from the data file, i want to calculate the sum total and average of the numbers and output the total and the average from the second code that reads the data file. what do i need to do to get to that to work?
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
//declarations
ofstream outputfile;
int num, integer, sentinel;
//open file for output
outputfile.open("savedata.dat");
//get input from user
cout << "How many integers would you like to enter? " << endl;
cin >> integer;
//use a for loop to get integers from user and store them in the file
for (int i = 0; i < integer; ++i)
{
cout << "Enter integer: " << endl;
cin >> num;
outputfile << num << endl;
}
//close file
outputfile.close();
return 0;
}
#include <iostream>
#include <fstream>
using namespace std;
int main()
{
//open file for input and read contents
ifstream inputfile;
int num;
inputfile.open("savedata.dat");
cout << "Contents of file: " << endl;
while (inputfile >> num) // read until end of file
{
cout << num << endl;
}
//close file
inputfile.close();
return 0;
}
tried adding int sum to find sum total but am lost

Answer 1

This is not that complicated. As per definition, the average can be calculated by divdiding the sum of the values by the count of the values.
So, we need to add 2 variables
counter --> To count the values in the file
sum --> To sum up the values
The variables will be defined and initialized to 0 before your read-loop.
In the for loop, we can simply incremented the counter add the newly read value to the sum. After the for loop, we can output all values. But we need to "cast" the values for "counter" and "sum" to a double value, because the average is typically not an integer.
Your second program could then look like the below:
int main()
{
main2();
//open file for input and read contents
ifstream inputfile;
int num;
inputfile.open("savedata.dat");
cout << "Contents of file: " << endl;
int counter = 0;
int sum = 0;
while (inputfile >> num) // read until end of file
{
cout << num << endl;
sum += num;
++counter;
}
//close file
inputfile.close();
cout << "\nNumber of value: " << counter << "\tSum: " << sum << "\t\tAverage: " << (double)sum/(double)counter << '\n';
return 0;
}