Thread: Beginner C programmer - My CSV reader

Hi,

Ive been trying to learn C programming. The project ive set myself is to make a CSV text file reader and parser. The aim of the program is to read a CSV file, then display it, breaking it down into its seperate values. I then want to be able to call individual pieces of information later on.

My current code looks like this:

Code:

#include <stdio.h>

int main(int argc, char ** argv){
  int c;
  FILE * fp;

  if(argc < 2){
    printf("Usage:\n\t%s filename\n",argv[0]);
    return -1;
  }

  if((fp = fopen(argv[1],"rb")) == NULL){
    printf("can't open %s\n",argv[1]);
    return -2;
  }

  while((c = fgetc(fp)) != EOF){
#define MAX_LINE_LEN   1024*512  /* 1/2 mega byte, should be more than sufficient */
.....

    char line[MAX_LINE_LEN];
   int len=0;
   int cnt_of_fields=0;
   char *p;
           switch(c)
           {
           case '"':
           case '\'':
                    /* parse a quoted string, ignore it for now */
                  break; 
           case ',':
                  ++cnt_of_fields; /* a comma signal end of previous field and begining of next fields */
                  line[len++]='\0';
                  if(len==MAX_LINE_LEN){
                           fprintf(stderr, "Line too long\n");
                           exit(-1);
                  }             
                 break;
           case '\n':
                ++cnt_of_fields; /* a EOL is end of record, and at the same time end of field */
                  line[len++]='\0';
                  
                 /* make a copy of the line in the heap, note strdup or strcpy won't work in our case */
                p = (char *)malloc(len); 
                memcpy(p, line, len); /* now all the fields in the record are stored in p[ ] */ 
                add_a_record( p );
                break;
           default:
                line[len++] = c;
                  if(len==MAX_LINE_LEN){
                           fprintf(stderr, "Line too long\n");
                           exit(-1);
                  }             
           }
   }
    printf( "%s", line );
  }

  fclose(fp);
  return 0;
}

The errors I get are attached in the image below. This is my first program, so I would really appreciate a little help working out why these errors are occuring, and also a little insight into if my code is the correct way of going about reading a csv file.

Regards,

James

Most of the errors are because of missing #includes.
You have to include

Code:

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

remove that line

Code:

.....

and there is a closing '}' too many. Proper indentation helps to find such errors.
Kurt

Hi,

Thank you very much for your help. I did the steps you told me, I deleted the ...., I added the headers and finally I deleted one of the } at the end, leaving me with two instead of three. This then gave me two remaining errors shown in the attached picture. The first is a warning, so I guess that wouldnt stop the program working. It says the add_a_record identifier is not found. What exactly does it mean by this, am i meant to define this somehow?

I got help on the forums with that bit of code so i dont really understand how I need to define add_a_record. What should the function add_a_record be doing?

That is a piece of code I got help with, im currently trying to intergrate it and understand why it works.