Storing input from file into struct in C - c

Question

So I have an input file that I'm scanning in. I also have an array of structs. I need to store the information from this input into the structs. I'm able to read the input file and print it back out but im not sure how to go about storing this information in my structs. The issue seems to be that I can't access my structs properly in the function that scans the file. Below is my code.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* make an array of structs that contain the ponds, and the ponds contain pointers to the circular lists */
struct pond_struct {
char name[20];
int sequence;
int failfish;
int eatingcounter;
int threshold;
struct pond_struct *next;
struct pond_struct *prev;
};
typedef struct pond_struct pond;
struct pond_list_struct {
pond *head;
pond *tail;
};
typedef struct pond_list_struct pond_list;
int get_number_of_ponds(FILE *ifp)
{
char s[128];
int num;
//get the first line of the file
fgets (s, 127, ifp);
if(isspace(s[0]))
{
fgets (s, 127, ifp);
}
sscanf(s, "%d", &num);
return num;
}
void remove_crlf(char *s)
{
char *t = s + strlen(s);
// t begins at the null sentinel at the end of s.
t--;
/* t is now at the last character of s - unless s didn't contain any characters, in which
case, t is now *BEFORE* s. We have to keep checking for that. */
/* We repeat until EITHER t slides to the left of s, OR we find a character that is not a
line feed (\n) or a carriage return (\r). */
while ((t >= s) && (*t == '\n' || *t == '\r'))
{
*t = '\0'; // Clobber the character t is pointing at.
t--; // Decrement t.
}
}
void get_next_nonblank_line(FILE *ifp, char *s, int max_length)
{
s[0] = '\0';
while (s[0] == '\0')
{
fgets(s, max_length, ifp);
remove_crlf(s);
}
}
void read_pond (FILE *ifp, FILE *ofp, pond ponds)
{
char s[128];
char full_line[128];
int nponds;
int i;
int pond_number;
char name[128];
//char sequence_string[128];
int sequence;
//char failfish_string[128];
int failfish;
//char eatingcounter_string[128];
int eatingcounter;
//char threshold_string[128];
int threshold;
nponds = get_number_of_ponds(ifp);
printf("There are %d ponds\n", nponds);
fprintf(ofp, "There are %d ponds\n", nponds);
for (i = 0; i < nponds; i++)
{
get_next_nonblank_line(ifp, full_line, 127);
sscanf(s, "%d %s %d %d %d", &pond_number, name, &failfish, &eatingcounter, &threshold);
printf("The pond name is %s\n", full_line);
}
}
/* void print_pond (FILE *ofp, pond ponds, char* name, int sequence, int failfish, int eatingcounter, int threshold)
{
fprintf(ofp, "%s is pond number %d. The number of failfish is %d, the eating counter is %d, and the threshold is %d\n", name, sequence, failfish, eatingcounter, threshold);
} */
int main (void)
{
FILE *ifp;
FILE *ofp;
int nponds;
int i;
char name[128];
int sequence;
int failfish;
int eatingcounter;
int threshold;
pond ponds[10];
// change input file name
ifp = fopen("input.txt", "r");
ofp = fopen("output.txt", "w");
read_pond(ifp, ofp, ponds[0]);
/* for (i = 0; i < nponds; i++)
{
print_pond(ofp, ponds[i], name, sequence, failfish, eatingcounter, threshold);
} */
fclose(ifp);
fclose(ofp);
return 0;
}

Answer 1

typedef struct {
int nMyInt;
char szDate[6];
char filler[2];
} _MY_STRUCT;
_MY_STRUCT stMS;
stMS.nMyInt = 2;
strcpy(stMS.szDate,"10/19/2020");
Update your structure so byte-alignment storage is 8 bytes using a filler.
Use &stMS with fread/fwrite and sizeof(_MY_STRUCT) to read/write data.