Split/Parse a String after reading a Text File? - c

Question

I am trying to simply read in a basic text file, split each line into separate strings and rearrange/copy them onto a new text file. Is there any simple way to split and identify these strings to be added to a new file at the end of processing the lines?
My code so far:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
FILE *pFileCust
fPointer = fopen("Athletes.txt", "r");
char singleLine[150];
while (!feof(pFileCust)){
fscanf(singleLine, 150);
int id, name, sport;
fprintf(%d[0,6], %s[8,15], %s[16,22], id, name, sport);
}
fclose(fPointer);
return 0;
}
Example Text File to be read into the program:
88888 John Doe Tennis
99999 Jane Smith Softball
Example Output that I am trying to achieve.
Tennis 88888 John Doe
Softball 99999 Jane Smith

Answer 1

Each line in your file corresponds to a record. Each series of consecutive non-whitespace characters corresponds to a field in the current record. Accordingly,
/* getrecord: read next record on fp */
char *getrecord(FILE *fp)
{
assert(fp);
char *line = malloc(MAXLINE);
if (line != NULL)
if (fgets(line, MAXLINE, fp) != NULL)
return line;
return NULL;
}
/* getfield: read next field in record */
char *getfield(const char *record, int *pos)
{
assert(record && pos);
char *record;
int ret;
if ((record = malloc(MAXRECORD)) != NULL) {
ret = sscanf(record + *pos, "%s", record);
if (ret == 1)
return record;
}
return NULL;
}
While each function does not appear to do much work, separating your business logic from record/field reading has real benefits. It allows extensibility (for example you can add error handling to these routines). You can also make more sense of your code. Now you can write your main function which will use this pair of calls.

Answer 2

Here is a simple adaptation of your code that (a) compiles, and (b) generates the output that you desire.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
FILE *pFileCust = fopen("Athletes.txt", "r");
char first_name[100], last_name[100], sport[100];
int id;
while (fscanf(pFileCust, "%d %s %s %s", &id, first_name, last_name, sport) != EOF) {
printf("%s %d %s %s\n", sport, id, first_name, last_name);
}
fclose(pFileCust);
return 0;
}
One of the key things your app was missing was anything assigning values to your variables; your fscanf was not doing anything (if it even compiled). fscanf is not a very GOOD way to parse text, it's not very robust. But for the principle of understanding how variables are assigned, please look carefully at that, and in particular understand why the id has an ampersand in front of it. Also, make sure you understand why I used both a first name and a last name.