Чтение чисел из файла .dat и вычисление стандартного отклонения

Я предполагаю прочитать числа из файла .dat, а затем вычислить стандартное отклонение, а также вывести количество чисел в файле. Я считаю, что мои средние значения и функции стандартного отклонения верны. Это фактический ввод чисел из файла в функции, которые меня отталкивают. Вот что у меня так далеко.

#include "pch.h"#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
#include <cmath>

using namespace std;

const int MAX_COUNT = 1000; //for max size of array

double Mean(double*, int); //calculates average of numbers
double Standard_Deviation(double*, int); //calculates standard deviation

void Magic_Number();

ifstream InFile;

int main()
{
Homework_Header();

string NameOfInputFile = "StdDev.dat";

InFile.open("StdDev.dat");
if (InFile.fail()) {
cout << "Cannot open file: " << NameOfInputFile << "\d";
exit(1);
}

int SamplePoint = 0;
double dataPoint[MAX_COUNT];
double sd = Standard_Deviation(dataPoint, MAX_COUNT);

while (InFile >> dataPoint)
{
void Magic_Number();

sd = Standard_Deviation(dataPoint, MAX_COUNT);

SamplePoint++;
if (InFile.eof())break;
}
cout << "The Standard Deviation is: " << sd << endl;
cout <<SamplePoint << " records process \n";InFile.close();

if (InFile.fail()) {
cout << "Cannot close file: " << NameOfInputFile << "\d";
exit(-5);
}

cin.get();
return 0;
}void Magic_Number()
{
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
}

double Mean(double* numbers, int count)
{
double calculated_mean = 0.0;

for (int i = 0; i < count; ++i)
{
calculated_mean += numbers[i];
}
calculated_mean /= double(count);

return calculated_mean;
}

double Standard_Deviation(double* numbers, int count) // * is pointer: special variable that has a memory address as value
{
double std_dev = 0.0;
double average = Mean(numbers, count); //Mean of numbers
double temp_dev;

for (int i = 0; i < count; ++i)
{
temp_dev = numbers[i] - average; //sets temp_dev to be the deviation from the average

std_dev += temp_dev * temp_dev; //adds squares of the deviations
}

std_dev /= double(count);

std_dev = sqrt(std_dev); // square roots

return std_dev;
}

1

Решение

#include "pch.h"#include <iostream>
#include <cmath>
#include <fstream>
#include <string>

using namespace std;

double Calc_Stand_Dev(ifstream &);

void Magic_Number();

ifstream InFile;

const int MAX_NUM = 1000;

int main()
{
string NameOfInputFile = "StdDev.dat";

InFile.open("StdDev.dat");
if (InFile.fail()) {
cout << "Cannot open file: " << NameOfInputFile << "\d";
exit(-3);
}

double sd = Calc_Stand_Dev(InFile);

cout << "The standard deviation is: " << sd << endl;

//cout << RecordCount << " numbers total are used to calculate the standard deviation. \n";

InFile.close();
if (InFile.fail()) {
cout << "Cannot close file: " << NameOfInputFile << "\d";
exit(-5);
}
cin.get();

return 0;
}

double Calc_Stand_Dev(ifstream & InFile)
{
double dataPoint[MAX_NUM], Avg, Variance, stdDev, sum = 0, sumSq = 0;
int RecordCount = 0;

for (int i = 0; i < MAX_NUM; i++)
{
InFile >> dataPoint[i];
Magic_Number();

sum += dataPoint[i]; //sums each new data point added from the file
sumSq += (dataPoint[i] * dataPoint[i]); //squares the data points and makes a sum out of it.

++RecordCount; // coutner for number of data points
if (InFile.eof())break;
}

Avg = sum / RecordCount;
Variance = (RecordCount * sumSq - sum * sum) / (RecordCount * (RecordCount - 1));
stdDev = sqrt(Variance);

cout << RecordCount << " numbers processed \n";

return stdDev;
}

void Magic_Number()
{
cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);
}
0

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