variance and mean

[grcarr77]

I have to output Mean and Variance, I can get output for Mean but not the Variance. Can you please look at my code and help me on how to input code for the Variance.

//variance.cpp

#include<iostream>

#include <fstream>

#include <math.h>

using namespace std;

float sum (float (*) (float, int), int*, int s);

float var (float, int);

ifstream infile ("array.dat");

int main(){

int array = 10;
int s = 0;
int a[array];
while(infile >> a[s]) {s++;}

cout << "Mean = " << sum(NULL, a, s) << endl;

cout << "Variance=" << sum(var, a, s) << endl;

cout << "\n\n\nPress any key to close console window: ";

char c; cin >> c;

return 0;

}

float sum (float (*pf) (float mean, int), int *n, int s) {

float sum=0; int *p=n;

float mean=0;

mean = sum / s;

for (int i=0; i<s; i++) {

if (pf == NULL) sum+= *p;

else sum+= (*pf)(mean, *p);

p++;

}

return sum/(s);

}

float var (float mean, int k)

{

return k*k;

}

[kbw]

Why oh why don't you just have two functions called variance and mean that calculate the variance and mean respectively?

Does infile need to be global?

Does that even compile?