Standard Deviation/Logic Error

[Stabby222]

Hello all! I'm currently working on a piece of homework where i have to calculate the average, min/max, and standard deviation of the file List.txt which contain about 500 random numbers.

Right now i'm working on trying to get a working standard deviation function in my program. As of right now, there are no syntax errors, but for some reason when compiling the program the following occurs:

-Calling the standard deviation in MAIN displays nothing. Not even the comment listed before the actual output of the function.

As of the time being let's focus on the double /*getSD(int vin[], int dsize);*/
function, and any other noticeable errors after that :) !

I hope this source code will possibly help others once cleaned up as well, as i see a lot of void/value function questions on the forum :3

So what could be going on here? :O

//This program does the following:
//	Input:
//		List.txt data file
//	Output:
//		Build array of values from data
//		calculate mean/max/min/standard deviation
//		quartile analysis

#include <iostream>
#include <iomanip>
#include <fstream>
#include <cmath>
#include <algorithm> 
using namespace std;

const int INDEX = 500;
int theData[INDEX];

//Prototypes
void getData(int[INDEX], int&);
void getData(ifstream& fin, int vin[], int& vnum);
double getAverage(int vin[], int dsize);
double getMax(int vin[], int vnum);
double getMin(int vin[], int vnum);
double getSD(int vin[], int dsize);

int main()
{
int Enum = 0;
double mean = getAverage(theData, Enum);

cout << "|** Score Analysis **|" << endl << endl;
//Open data file
fstream fin;
fin.open("List.txt");

//Check if file opened correctly
if (fin.fail() )
{
	cout << "Problem opening file";
	//cin.get();
	exit(-1);
}

//Establish max boundaries for index size
while (Enum < INDEX && !fin.eof())
{
	fin >> theData[Enum];
	++Enum;
}

//Average Calculation
cout << "Average Score: " << setprecision(2) << setw(4) << getAverage(theData, Enum) << endl;
mean = getAverage(theData, Enum);
//Max Calculation
cout << "Max Score: " << setprecision(2) << setw(4) << getMax(theData, Enum) << endl;
//Min Calculation
cout << "Min Score: " << setprecision(2) << setw(4) << getMin(theData, Enum) << endl << endl;
//Standard Deviation Calculation
cout << "Standard Deviation: " << setprecision(2) << setw(4) << getSD(theData, Enum) << endl;

//Close File
fin.close();

system("pause");
return 0;
}

//****Functions****\\

void getData(int[INDEX], int& dsize)
{
	dsize = 0;
	ifstream fin;
}
void getData(ifstream& fin, int vin[], int& vnum)
{
	int i = 0;
	fin >> vin[i];
	while (!fin.eof() && i < INDEX)
	{
		i++;
		fin >> vin[i];
	}
	vnum = i;
}
double getAverage(int vin[], int dsize)
{
	double sum = 0.0;
    
    for (int i = 0; i < dsize; i++)
       sum = sum + vin[i];    
       
    return sum / dsize; 
}
double getMax(int vin[], int vnum)
{
	int max = vin[0], i = 0;
	for(i=0; i < vnum; i++)
	{
        if (max < vin[i]) 
            max = vin[i];
	}
	return max;
}
double getMin(int vin[], int vnum)
{
	int min = vin[0], i = 0;
	for(i=0; i < vnum; i++)
	{
        if (min > vin[i]) 
            min = vin[i];
	}
	return min;
}
double getSD(int vin[], int dsize)
{
	double sum = 0.0, sum2 = 0.0, avg = 0.0, variance = 0.0;
	double SD = 0.0;

    for (int i = 0; i < dsize; i++)
		sum = sum + vin[i];    
	avg = sum / dsize; 
	
	for (int i = 0; i < dsize; pow((i - avg),2))
		sum2 = sum2 + vin[i];
	return SD = sum2 / dsize;
}

[Stabby222]

Anybody? D:

[firedraco]

Inside the getSD function, what are you trying to do on line 125? The increment section doesn't do anything, so I would expect the loop to go forever.