C language to calculate mean,variance

Applications Programming
1

Here I want to calculate mean,variance and sum from a file
1.1*2*4*22*211*22*12*22*2211
2.2*2*22*12*22*11*11*122*3322
3.9*7*22*88*87*98*67*66*56*66*11
As this is a large file and i am trying to write in c

where formulae of

MEAN = 1/N (X1...+..Xn)
Variance = square root of 1/N-1 (X1+.,,Xn - mean)2

So simply question say in this example we have one file where first part want to calculate mean and variance
again second part calculate mean and variance ..respectively and save the result

#include <math.h>
void moment(float data[], int n, float *ave, float *var)

{
void nrerror(char error_text[]);
int j;
float ep=0.0,s,p;
if (n <= 1) nrerror("n must be at least 2 in moment");

s=0.0;
for \(j=1;j&lt;=n;j\+\+\) s \+= data[j];
*ave=s/n;

what will be the code for variance?
Can rewrite the program with mentioning of open file and closing of file
Thanks

2 
#include <math.h>
void moment(float data[], int n, float *ave, float *var)

{
    void nrerror(char error_text[]);
    int j;
    float ep=0.0,s,p;
    if (n <= 1) nrerror("n must be at least 2 in moment");
                                              
    s=0.0;
    for (j=1;j<=n;j++) s += data[j];
      *ave=s/n;
    variance = sqrt(pow((s - avg), 2)/(n - 1));
3

Is this a homework assignment?? I keep reading posts with really "interesting" program requirements that seem to only have a theoretical benefit.

4

ask the source code for variance that i have got..
home work assignment only if u don't attempt on a problem and writing questions only....
sorry if bother

5

Are you trying to find the mean & variance of all the data points in the file or for every line of the file?

:confused:

6

Dear Shamrock,
Here trying to derive mean and variance for every line of the file Hereby each line is just say as separate entity.
That is In one file Input is
1.1*2*4*22*211*22*12*22*2211 then derive its mean and variance
2.2*2*22*12*22*11*11*122*3322 same derivations......
continue............etc.etc....

7

So let me see if I understand your post. You need the mean & variance for every line of input and every one of those input lines has ten data values separated by the asterisk character and the first data value is a floating point number like 1.1 2.2 yada yada...correct me if I am wrong.
The code you have posted does not seem to be able to compute the mean and variance of every line of input.

8

Dear Shamrock,
Yes ,I need the mean and variance for every line of the input and every one of those input lines has ten data values separated by the asterisk character

But first data value is just 1 2 4 22 211 22 12 22 22 11
and 1. and 2.is just a serial number and can be ignored for that
sorry for that incovenience
if that code not work what can be possible solution? Can u rewrite it?

Thanks

9

Now you have everything you need to write this code. It should be a relatively small program. Scan each line into 10 variables computing its mean and variance.

10

Thanks