Why is my program stopping before reading the txt file? - c

Question

My code keeps closing before reading the file, I made a comment where it closes. Does anyone know why it wont work? I showed it to my lecturer but she couldn't figure it out and then she had to leave so I was wondering if anyone here could figure it out!
#include <stdio.h>
#include <stdlib.h>
#define RESULT_MAX = 100;
#define RESULT_MIN = 0;
int main()
{
int studentId;
char firstName[20];
char lastName[20];
int result;
FILE *fPtr;
if ((fPtr = fopen("student.txt", "w")) == NULL)
{
printf("File could not be opened\n");
//exit(0);
}
else
{
printf("Enter the Id, first name, last name and result\n");
scanf("%d %s %s %d", &studentId, firstName, lastName, &result);
while(!feof(stdin) )
{
fprintf(fPtr, "%d %s %s %d\n", studentId, firstName, lastName, result);
scanf("%d %s %s %d", &studentId, firstName, lastName, &result);
}
fclose(fPtr);
}//else end
// MY PROGRAM ENDS HERE AND WONT CONTINUE!
if ((fPtr = fopen("student.txt", "r")) == NULL)
{
printf("File could not be opened\n");
//exit(0);
}
else
{
printf("Id, first name, last name, result ");
fscanf(fPtr, "%d %s %s %d", &studentId, firstName, lastName, &result);
while(!feof(fPtr) )
{
printf("%d %s %s %d \n", studentId, firstName, lastName, result);
fscanf(fPtr, "%d %s %s %d", &studentId, firstName, lastName, &result);
}//end while
fclose( fPtr );
}//end if
}

Answer 1

the problem is actually the line: 'while(!feof(stdin) )'
because feof() only becomes valid when the program
tries to read past the end of the 'stdin' file.
This is something that cannot be accomplished
suggest
modifying the program to:
1) read into a local buffer[] array, in a loop,
2) using fgets() as the loop control
3) have a leading 'q' (or similar) as an indication of having read all input
4) output a prompt for every input line
5) if going to parse the fields, parse them using
strtok()/atoi() strncpy() strncpy() atoi()
or perhaps
sscanf()
6) check first char of input buffer[] for the end marker (the 'q' above)
to exit the input loop before parsing
there is a similar problem with the
loop reading the file
I.E. do not use feof() for loop control
rather use fgets()
to differentiate each line of input written to the file, modify
the fprintf(fPtr, ... ) format string to include a trailing '\n'