Program to calculate the mean and standard deviation of a set of inputs from a file. Created for CSCI course by Sam Couch

gistfile1.cpp

#include <iostream>
#include <iomanip>
#include <cmath>
#include <fstream>
#include <string>
//------------------------------------------------------------------------------
using namespace std;
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
bool GetInputOpenFile(ifstream  &inFile, string &name);
//------------------------------------------------------------------------------
bool isEmpty (string &name);
//------------------------------------------------------------------------------
double stdDev(double s[], int size);
//------------------------------------------------------------------------------
double mean(double s[], int size);
//------------------------------------------------------------------------------
int getPrecision ();
//------------------------------------------------------------------------------
//Function declarations:
//------------------------------------------------------------------------------
bool GetInputOpenFile(ifstream  &inFile, string &name)
{
	cout << "\n\nPlease enter the name of the input file: " << flush;
	getline(cin, name);
	inFile.open(name.c_str());
	if ( inFile.fail() )
		return false;
	return true;
}
//------------------------------------------------------------------------------
double stdDev(double s[], int size)
{
	double sum = 0;
	double avg = mean(s, size);
	for (int i = 0; i < size; i++) 
	{
	sum += pow(s[i]-avg, 2);
	}
	return sqrt(sum/size);
}
//------------------------------------------------------------------------------
double mean(double s[], int size)
{
	double sum = 0;
	for (int i = 0; i < size; i++) 
	{
	sum += s[i];
	}
	return sum / size;
}
//-----------------------------------------------------------------------------
int getPrecision()
{
	int nDec;
	cout << "\nEnter the desired number of decimal places for the output: " << flush;
	cin >> nDec;
	return nDec;
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
int main()
{
	ifstream inputFile;
	string inputFileName;
	int size = 0, nDec;
	double numbers[1000], total;

	cout << "In this program, we will calculate the mean and standard deviation of a set of"
		 << "\nnumbers in a specified file.";
	while (!GetInputOpenFile(inputFile,inputFileName))
	{
			cout << "\n*****             ERROR             *****"
				 << "\n*****        Could not open the input file."
				 << "\n*****        File name: " << inputFileName
				 << "\n*****        It is possible that the file does not exist or "
				 << "\n*****        was entered incorrectly."
				 << "\n\nHit enter to try again: " << flush;
			cin.get();
	}
	while (!inputFile.eof())
	{
		inputFile >> numbers[size];
		size++;
	}
	cout << fixed << setprecision(getPrecision())
		 << "\n\n              Mean: " << mean(numbers, size)
		 << "\nStandard Deviation: " << stdDev(numbers, size)
		 << "\n\nHit enter to exit: " << flush;
	cin.get();
	cin.get();
	return 0;
}