one small help

Dear members,
i need a small help in C programming..
I have a file with two columns
column one starts from 0,1,2,3,.......may be up to 1000
column two contains some numbers...may be integer and/or some numbers
but the two columns are +ve...
Now i need to change/multiply column one with a constant number, K, which may be up to 3 decimal places...and then divide by the last number (in this case 1000) from column one.
then the second column need to be divided by a number M, through out...
So i need to write the new values in a new file...
its better for me give input and output file name from command and also the K and M...in this the 1000 shall be selected automatically...
if anyone willing to help me...

advance thanks,
kumar

What have you tried?

read file using fgets in a loop like

Code:

---

while(fgets(buf, sizeof buf, fp))
{
  /* process buf */
}

---

parse the buffer using scanf or strtol or some other method
fill the array of numbers...
calculate the last index in the first column

then - use loop to write the result of calculation based on the array and stored index into the new file

post your code attemp and ask about problems you failed to achive

do one thing at a time - do not get to the next step till you successfully finishe the previos one

So what's your actual difficulty?

I am new to C...
i know only very little......
can some one pls. write me the code??

thanks
kumar

Kindly read about our homework policy.

<< !! Posting Code? Read this First !! >>
Cprogramming.com: How to Get Started with C++
Cprogramming.com - Programming Tutorials: C++ Made Easy and C Made Easy
Cprogramming.com: FAQ
C Book Recommendations
C++ Book Recommendations - C Board
cplusplus.com - The C++ Resources Network

I understand...this is not like a home work...all these days i use excell...but now i feel C would be more good...

does anyone have bohariho's email id????

Forget those guys... being so unkind and heartless to a poor student. With the cost of school ever increasing my heart goes out to you.

But since I prefer PERL for this type of operation, you get what you get.

Code:

---

# may as well multiply by e  and pi :)
$K = 2.718
$M = 3.142

open(NUMBERIN, "<mycolumns.txt")
open(NUMBEROUT, ">mynewcolumns.txt")

@lines = <NUMBERIN>
@nums = split(/ /, $lines[-1])
$N = $nums[0]

foreach $line(@lines) {
  @nums = split(/ /, $line)
  $nums[0] *= $K / $N
  $nums[1] /= $M
  print NUMBEROUT "$nums[0] $nums[1]\n"
}

close(NUMBERIN)
close(NUMBEROUT)

---

I hope that helps.

Quote:

---

Originally Posted by kumaravel_futu

I understand...this is not like a home work...all these days i use excell...but now i feel C would be more good...

---

For this I think Excel would actually be the optimal choice. You can do stuff like this in C, but if all you need is the output, then Excel would be so much simpler...

hi master thanks,,,
anyways i write my own code and inform u..may be tomorrow i will do it...now 50% finished..

Yes excel is better...for may complex calculation i do it in excel!!!but its time consuming..so if i have some C codes..then its really efficient...Also i am not a programmer.....yes i have time i can do like u guys...
anyways tomorrow i will tell abt. my c codes
kumar

Good luck buddy. As for the time element, consider this: In Excel the time consuming element is data entry (which you already have the table it seems) whereas to develop a program you still have the time consuming element plus developmental time. Which in this case is marginal since to write something according to that specification takes around a minute or less.

I am not discouraging you from learning the trade. I just hope your rationale for picking it up isn't one that is susceptible to thinking there is little point in the pursuit.

Keep the questions coming though pal. They are always welcomed and sometimes answered with less immediate sarcasm. :)

Hi now i created my code...but with lots of error..pls. correct me...at least now can anyone help me out...
my input file looks like this:
0 1212.23
1 2323.45
2 5985.555
3 3778.7812
4 45.56
. .
. .
. .
(N-1) .

that is two columns...if the last number in 1st column is (N-1), then the total no. of points is (N)...hope u understand...Now i need to make the following conversion to column one:-
2*V*(i-Z)/(N-1), where V = is some no. for e.g., 5.786, and Z = 456.5643356 and (N-1) is the last no. of column one or total no. of data points. And i=0,1,2,3,...(N-1).
Also for the second column i have to do the following conversion:-
(M*100/K), where M is the values in second columns (for e.g., 1212.23, 2323.45, etc.) and K is some number for e.g., 12312555.5555567.
So in the command line i need to type the exe file name, input files name, output file, Z, V and K.
Here my code:-

Code:

---

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>

#define LNGMAX 1500

int main(int argc, char **argv)
  {
  FILE *fpein,*fpaus;
  char *fs,datein[LNGMAX],dataus[LNGMAX],zeile[LNGMAX];
  double V,Z
  int ndat

  if (argc != 6)
    {
    puts(" !!! Aufruf: vel <datein> <dataus> <Z> <V> <K> ");
    puts(" ... Z  : 57Fe's zero velocity channel");
    puts(" ... V  : Drive velocity in mm/s");
    return(-1);
    }
  strcpy(datein,argv[1]);
    if ( (fpein=fopen(datein,"r")) == NULL )
    { printf("\n !!! Error %s cannot open\n",datein);
      return(-1); }
  strcpy(dataus,argv[2]);
  if ( (fpaus=fopen(dataus,"w")) == NULL )
  { printf("\n !!! Error %s cannot open\n",dataus);
    return(-1); }

  sscanf(argv[3],"%lf",&Z);
  sscanf(argv[4],"%lf",&V);
  sscanf(argv[5],"%lf",&K);

/* det. no. of data points */

  i=0;
    do {
        fg=fgets(zeile,LNGMAX,fpein);
       
        sscanf(zeile,"%lf" %lf\n",&x[i],&y[i]);

        i++;
    } while (fg!=NULL);
    fclose(fpein);
    ndat = i-1;

for i=0;i<=LNGMAX;i++)
i=0;
do {
  x[i]=2*V*(i-Z)/(ndat-1);
  i++;
      } while (fg!=NULL);
do {
  i=0;
  y[i]=i/K;
} while (fg!=NULL);

fprintf ( fpaus," %lf  %lf\n", x[i],y[i]);
fclose(fpaus);
puts("....Done");
return(0);
}

---

correct this c code..

thanks
Kumar.#