#include <study.hpp>
 
// Lesson:  Find average of several doubles
// Every exercise will consist of a number of non-negative doubles.  After all
// are read, the stream will become invalid.
 
// Syntax: Check stream state to see if there is more data for this exercise.
// MAIN is called externally, once for every exercise.
 
int MAIN()
{
	double d;
	double total = 0.0;
	int count = 0;
	while (study::cin >> d) // Will be true until all data is read.
	{
		total += d;
		++count;
	}
	study::cout << (total/count) << study::endl; // Submits the answer.
	return 0;
}
 

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