/* AddCols.c */
/* program to read a text file and add extra columns of text */
/* first argument is input file name */
/* second argument is output file name */
/* next arguments are extra columns (up to 10) */


/* standard system headers */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


int main(int argc, char* argv[])
{
  int nCols, i, j;
  char* inName;
  char* outName;
  char** col;
  FILE* inFile;
  FILE* outFile;
  char line[100];
  char* flag;
  
  /* check argument count */
  if (argc <4 || argc > 14)
  {
    printf("AddCols: inFile outFile col1 <col2 col3 ...> \n");
    exit(1);
  }
  
  /* aliases for arguments */
  inName=argv[1];
  outName=argv[2];
  col=&argv[3];
  
  /* number of columns */
  nCols=argc-3;

  /* echo input */
  printf("AddCols: inFile='%s' outFile='%s' cols=", inName, outName);
  for (i=0; i<nCols; i++) printf(" %s", col[i]);
  printf("\n");
  
  /* check that input and output files are different */
  if (!strcmp(inName, outName))
  {
    printf("Error: inFile=outFile\n");
    exit(1);
  }
  
  /* open input file */
  inFile=fopen(inName, "r");
  
  /* check that it opened */
  if (inFile == NULL)
  {
    printf("Error opening inFile='%s'\n", inName);
    exit(1);
  }
  
  /* open output file */
  outFile=fopen(outName, "w");
  
  /* check that it opened */
  if (outFile == NULL)
  {
    printf("Error opening outFile='%s'\n", outName);
    exit(1);
  }
  
  /* loop over lines */
  for (j=0; j<99999; j++)
  {
    /* read a line from input file */
    flag=fgets(line, 100, inFile);
    
    /* exit loop on end of file, etc */
    if (flag == NULL) break;
    
    /* remove the newline character */
    line[strlen(line)-1]=0;
    
    /* write line to output file */
    fprintf(outFile, "%s", line);
    
    /* write extra columns */
    for (i=0; i<nCols; i++) fprintf(outFile, " %s", col[i]);
    
    /* terminate the line */
    fprintf(outFile, "\n");
  }
  printf("wrote %i lines to outFile='%s'\n", j, outName);
    
  return 0;
}