Question

I have a tab delimited file that I am trying to convert to a tab delimited file. I am using C. I am getting stuck on trying to read the second line of the file. Now I just have an tens of thousand of lines repeating the first line.

#include <stdio.h>
#include <string.h>
#define SELLERCODE  A2LQ9QFN82X636

int main ()
{
     typedef char* string;
     FILE* stream;
     FILE* output;
     string asin[200];
     string sku[15];
     string fnsku[15];
     int quality = 0;

     stream = fopen("c:\\out\\a.txt", "r");
     output = fopen("c:\\out\\output.txt", "w");

     if (stream == NULL)
     { 
         perror("open");
         return 0;
      }

     for(;;)
     {
       fscanf(stream, "%[^\t]\t%[^\t]", sku, fnsku);
       printf("%s\t%s\n",  sku, fnsku);
       fprintf(output, "%s\t%s\t%\t%s\t%s\t%i\n", sku, fnsku, asin, quality);
     }

}

Answer 1

Prefer fgets() to read the input and parse the lines in your program, using, for example, sscanf() or strtok().

fscanf is notoriously difficult to use.
Your fscanf is not performing any conversions after the first line.
It reads characters up to a TAB, then ignores the TAB, and reads more characters up to the next TAB. On the 2nd time through the loop, there is no data for sku: the 1st character is a TAB.

Do check the return value though. It helps enormously.

chk = fscanf(stream, "%[^\t]\t%[^\t]", sku, fnsku);
/* 2 conversions: sku and fnsku */
if (chk != 2) {
    /* something went wrong */
}