# Average of a stream of numbers in C++

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Average of numbers is the sum of numbers divided by the total number of numbers.

In this problem, we are given a stream of numbers. And we will print average of the number at every point.

Let’s take an example of how it works −

We have a stream of 5 number 24 , 76 , 29, 63 , 88

The average at each point of the stream would be −

24 , 50 , 43 , 48 , 56.

For this we will find the average of the stream every time a number is added to the stream. So, we need to find the average of 1 number , 2 numbers , 3 numbers and so on. We will make use of previous average for this.

## Algorithm

Step 1 : for i -> 0 to n (length of stream).
Step 2 : find the average of elements using formula :
Average = (average * i) + i / (i+1)
Step 3 : print average.

## Example

Live Demo

#include <iostream>
using namespace std;
int main(){
int arr[] = { 24 , 76 , 29, 63 , 88 };
int average = 0;
int n = sizeof(arr) / sizeof(arr[0]);
for(int i = 0 ; i< n ; i++){
average = ((average * i) + arr[i]) / (i+1);
cout<<"The average of "<<i+1<<" numbers of the stream is "<<average<<endl;
}
return 0;
}

## Output

The average of 1 numbers of the stream is 24
The average of 2 numbers of the stream is 50
The average of 3 numbers of the stream is 43
The average of 4 numbers of the stream is 48
The average of 5 numbers of the stream is 56

The same algorithm is applicable for all data types. And can be used to calculate the average of stream at every point.

Updated on 24-Oct-2019 10:48:19