/****************
  data_read.c by Michael J. Scott April 17, 1997   for ME171
  reading the file in.dat
***********/

/****************
  I changed this file a little bit from the original one to make it work well,
  so it's not the same as the handout. Also note that this code is intended 
  to be illustrative, not garanteed bug_free.  -----Lin.
**************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define N 4
#define MAXVECTORS 3000 /* more vectors than we can imagine wanting to read 
			   alternatively (and better), use dynamic allocation.
			   Not required, however */

void main(){

  FILE *fpin,*fpout;
  int i,j,vectors;
  char oneline[80];
  double vec[MAXVECTORS][N];

  /******* read in the data file ********/
  fpin = fopen("in.dat","r");
  vectors=0;
  while(fgets(oneline,80,fpin)){    /* as long as there are lines to read */
    if(strchr(oneline,'&')){        /* if it's an ampersand, notice */
      printf("Got an ampersand.\n");
      vectors--;
    }
    else {
      if(sscanf(oneline,"%lf %lf %lf",&vec[vectors][0],&vec[vectors][1],
		&vec[vectors][2])!=3){ 
	          /* ignore lines that don't have three doubles */
	printf("oops\n"); 
	vectors--;
      }
    }
    vec[vectors][3]=1.;
    vectors++;  /* keep track of how many vectors we've read.
		   note you have to decide what to do with the &'s;
		   */
  }
  fclose(fpin);

  printf("%d\n",vectors);
  /******* write the output file *******/
  fpout = fopen("out.dat","w");
  for(i=0;i<vectors;i++){
    for(j=0;j<2;j++){
      fprintf(fpout,"%.4f ",vec[i][j]/vec[i][3]);
    }
    fprintf(fpout,"\n");
  }
  fclose(fpout);

  /*****
  in your program you may combine the reading and writing together, read 
  a line from in.dat, check if it's "&", then write it to out.dat in proper 
  format.
  *****/

}