Programming

Hi I was hoping that maybe someone could help me with a small piece of C code. I have a number of files, which are all of similar layout ie. three lines of text and 5-6 columns of numerical data. I need to add each of the elements of the second column in one file to their counterparts in the second column of the other file. I must add them in the ratio of 3:1 so I also need to multiply one column by a scalar. So I need to extract the files (into an array?), manipulate the data, add the array elements into a new array, and return this as a file. I think. Any help anyone could provide would be greatly appreciated as this problem is really holding me up. Thanks very much.

is it is constraint that it has to be done in c? can you opt for shell script? (You have this posted in the C forums)
well not that it cant be done in c. but parsing the files is gonna take away all the zeal.
if you can consider scripting you can think of awk (nawk) as substitutes, let us know

No i suppose C isn't necessarily the only option. The reason i was opting for it was its the only language i have any knowledge of; minimal as that knowledge is. Programming is something i've had little contact with and i've only a pretty basic understanding of it. So whatever you reckon would be the easiest method to solving my problem. And this is probably a very "rookie" question, but whats awk/nawk? Thanks for your reply.

Post some sample data. Also tell us what kind of unix you have. The command uname -a will tell you.

Its Red Hat, version 9 i think. I don't have the actual data with me now but i can give you an example:

Code:

% This is a file containing the flux at varying wavelengths
% of a young massive star which is surrounded by a dust cloud. 
% Wavelength       Flux        Temp       O.D.
      0              0           x         x
      5              3E-6        x         x
     10             16E-5        x         x
     15             87E-3        x         x
      :              :           :         :
    200              0           x         x

The elements in the first column are always the same. I need to add together the Flux values at each wavelength, in the ratio of say 3:2 and put the result into a new file. The other columns are irrelevent. Thanks a million for any help you can give me.

That looks all wrong. Not the way i typed it up at all. Sorry. There are 4 seperate values in each row, one under each of the headings. So in line 2 5 is under "wavelength" , 3E-6 is under "flux", and an x (insignificant value) under both Temp and O.D.

Code:

nawk '{ arr[$1] += $2 }
END {
  for ( i in arr )
     print i, arr[i]
}' myFile