Strings and array of structures - c

Question

***UPDATED WITH NEW CODE
I'm trying to load a file data with an unknown amount of lines of data.
The data is organized as last, first:score1:score2:score3:score5:lettergrade
I'm getting the file to (sort of) load into an array and print.
When the data prints, it doesn't print the first name, just the first. It's printing the same integer for evert data element except for the last one, that comes out at 0 for all. Also, it's not flushing the data that doesn't return 8 elements.
PLEASE help!
Thanks in advance.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define FFLUSH while(fgetsc(fp) != '\n')
#define MAX_STUDENTS 45
typedef struct aStudent
{
char name[26];
int id[7];
int test1[4];
int test2[4];
int proj1[4];
int proj2[4];
int proj3[4];
char grade[4];
} aStudent;
int main(void)
{
char file_name[FILENAME_MAX];
FILE* fp;
int i;
int rc;
int dc;
aStudent studentArray[MAX_STUDENTS];
printf("Enter File Name: ");
rc = scanf("%s", &file_name);
if (rc == 0)
{
printf("\n\nError: No file name entered.");
exit(0);
}
fp = fopen(file_name, "r");
if (fp == NULL)
{
printf("Error: Could not open file %s for read", file_name);
exit(0);
}
for(int i=0; i< 45; i++)
{
dc = (fscanf(fp, "%s[^:]%d[^:]%d[^:]%d[^:]%d[^:]%d[^:]%d[^:]%f[^:]%c[^:\n]", studentArray[i].name, studentArray[i].id, studentArray[i].test1, studentArray[i].test2, studentArray[i].proj1, studentArray[i].proj2, studentArray[i].proj3, studentArray[i].grade));
if (dc != 8)
{
FFLUSH;
}
printf("%s %d %d %d %d %d %d %.2f %c", studentArray[i].name, studentArray[i].id, studentArray[i].test1, studentArray[i].test2, studentArray[i].proj1, studentArray[i].proj2, studentArray[i].proj3, studentArray[i].grade);
}
return 0;
}

Answer 1

STUDENT is a type. You cannot fgets into a type. There is no array STUDENT. Try this;
typedef struct aStudent
{
char name[26];
int id[7];
int test1[4];
int test2[4];
int proj1[4];
int proj2[4];
int proj3[4];
int ave[4];
char grade[4];
} aStudent;
and;
aStudent studentArray[MAX_STUDENTS];
and replace gGets with fscanf.

Answer 2

It appears you have your struct set up incorrectly to handle the data you want to read from your file. Your data was:
name:score1:score2:score3:score5:lettergrade
A struct that makes sense (given the multiple scores) would be:
typedef struct {
char name[MAXNM];
int id;
int scores[NGRDS];
float ave;
char grade;
} student;
(you have never accounted for where the id comes from and I'll leave it to use to split name into first, last, as your original question specified name and your recent edits added first, last)
What is clear is you want to read your datafile into a struct and compute the ave (average) from the grades read (which should be a floating-point type instead of int). Given your file format, reading each line of data with the scanf family functions is probably a bit more sensible than reading/tokenizing each line with fgets/strtok.
Your mixing of fgets and fscanf syntax will not work and exemplifies the difficulty in trying to shoehorn mixed data into a scanf type format string. You must take care in crafting the string to handle whitepace and any trailing newlines left in the input buffer. For your set of data, the following will work as well as anything else:
char *fmt = " %[^:]:%d:%d:%d:%d:%c";
Another way to account for the trailing newline is to use the assignment suppression operator to read and discard the trailing newline. When used, the discarded conversion is not added to the returned match count. e.g.
char *fmt = "%[^:]:%d:%d:%d:%d:%c%*c";
There is no need for macros to flush the input buffer if you craft your format string correctly.
Putting the pieces together, and leaving your belated change from name to last, first to you, you could do something like the following:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* constants for:
NGRDS - max number of grades per student.
MAXNM - max length of student name.
MAXSTD - max number of students in array.
MAXFN - max filename length.
*/
enum { NGRDS = 4, MAXNM = 26, MAXSTD = 45, MAXFN = 128 };
typedef struct {
char name[MAXNM];
int id;
int scores[NGRDS];
float ave;
char grade;
} student;
int main (void) {
char filename[MAXFN]; /* initialize variables */
char *fmt = " %[^:]:%d:%d:%d:%d:%c";
FILE* fp = NULL;
size_t i = 0, nstudents = 0;
student students[MAXSTD] = {{ {""}, 0, {0}, 0.0, 0 }};
printf ("\nEnter File Name: ");
if (scanf("%s", filename) != 1) { /* validate filename read */
fprintf (stderr, "error: invalid file name entered.\n");
return 1;
}
if (!(fp = fopen (filename, "r"))) { /* validate file open */
fprintf (stderr, "error: file open failed '%s'\n.", filename);
return 1;
}
/* read each line in file */
while (fscanf (fp, fmt, students[i].name, &students[i].scores[0],
&students[i].scores[1],&students[i].scores[2],
&students[i].scores[3], &students[i].grade) == 6) {
int j; /* compute sum/average */
for (j = 0; j < NGRDS; j++) students[i].ave += students[i].scores[j];
students[i].ave /= (float)NGRDS;
if (++i == MAXSTD) { /* check against max */
fprintf (stderr, "warning: students array full.\n");
break;
}
}
fclose (fp); /* close file */
nstudents = i; /* save number of students */
for (i = 0; i < nstudents; i++) { /* output student data */
size_t j;
printf ("\n Student[%2zu]\n name : %s\n scores :",
i, students[i].name);
for (j = 0; j < NGRDS; j++) printf (" %d", students[i].scores[j]);
printf ("\n average: %.2f\n grade : %c\n",
students[i].ave, students[i].grade);
}
return 0;
}
Example Data
$cat dat/studentgrades.txt
Joe Cool:80:77:63:88:c
Nancy Smart:96:93:97:99:a
Dwane Dumb:61:60:67:50:f
Al Smith:75:77:78:73:c
Example Use/Output
$ ./bin/studentstruct
Enter File Name: dat/studentgrades.txt
Student[ 0]
name : Joe Cool
scores : 80 77 63 88
average: 77.00
grade : c
Student[ 1]
name : Nancy Smart
scores : 96 93 97 99
average: 96.25
grade : a
Student[ 2]
name : Dwane Dumb
scores : 61 60 67 50
average: 59.50
grade : f
Student[ 3]
name : Al Smith
scores : 75 77 78 73
average: 75.75
grade : c
(note: your letter grade should be computed based on the average, not simply read from the file -- what if the grades change? Also note that your input file format is fixed and inflexible. If the number of fields or their format changes in any way, you must account for the change in your fmt format string.)
Look it over and let me know if you have any questions.