How do I print the contents of a struct in C? - c

Question

Resolved the issues on my own, using different methods than those suggested below! :)
Thanks for viewing my question! :)
I've been learning about structs and working on a practice lab in C, and my code does not seem to be compiling correctly with any change I make to it. Currently I am not receiving any output and the program crashes. I'm still very confused on how to correctly utilize the '*' and '&' symbols when passing them into functions as well. My goals for this practice are to:
print the contents of the array in the same format as the data file
print the full name of the student with the best GPA
calculate and print the average GPA
print the names of all students with GPAs above the average
print the name of the youngest student who has a GPA below average
sort the structures in the array into order from lowest to highest
GPA
print the array again (will now be in a different order from last
time)
How do I properly call to and print these items from the student struct? And how would I access the gpa values to pass into a function that would calculate the average?
#include <stdio.h>
#include <stdlib.h>
// define constants
#define ARR 100
#define FIRST 7
#define MIDINIT 1
#define LAST 9
#define STREET 16
#define CITY 11
#define STATE 2
#define ZIP 5
#define AGE 3
#define GPA 4
#define START 0
#define FIRSTID 8
#define INITID 10
#define STREETID 20
#define CITYID 37
#define STATEID 49
#define ZIPID 52
#define AGEID 57
#define GPAID 64
// defined structs
typedef struct {
char street[STREET + 1];
char city[CITY + 1];
char state[STATE + 1];
char zip[ZIP + 1];
} Address;
typedef struct {
char firstname[FIRST + 1];
char initial[MIDINIT + 1];
char lastname[LAST + 1];
Address ofstudent;
int age;
double gpa;
} Student;
// function prototype
void strsub(char buf[], char s[], int start, int size);
void processStudent(int *id, Student students[]);
void sortStudentGpa(Student *students, int id);
void maxGpa(Student *students, int id);
/* lab6student.c: creates an array of student structures and outputs reports */
int main(void)
{
Student students[ARR]; // creates an array of student structures
int id = 0; // counter for student
processStudent(&id, students);
maxGpa(students, id);
}
void strsub(char buf[], char s[], int start, int size) {
int i;
for (i = 0; i < size && buf[start + i] != '\0'; i++) {
// loops as long as iterator is less than size
// and while string has not run out of characters
s[i] = buf[i + start];
}
s[i] = '\0';
}
/* void sort(Student *students, int id) {
int j, i;
for(i = 1; i < n; i++) {
for(j = 0; j < id - i; j++) {
if(students[j].gpa > students[j + 1].gpa) {
Student temp = students[j];
students[j] = students[j + 1];
students[j + 1] = temp;
}
}
}
} */
void processStudent(int *id, Student students[]) {
FILE *data;
char line[ARR];
*id = 0; // counter for student
data = fopen("Students.dat", "r");
if (data == NULL) {
printf("Students.dat file not found!\n");
exit(1);
}
// process file
while (!feof(data)) {
// organize student info into separate arrays
fgets(line, ARR, data);
strsub(line, students[*id].firstname, START, FIRST);
strsub(line, students[*id].initial, FIRSTID, MIDINIT);
strsub(line, students[*id].lastname, INITID, LAST);
strsub(line, students[*id].ofstudent.street, STREETID, STREET);
strsub(line, students[*id].ofstudent.city, CITYID, CITY);
strsub(line, students[*id].ofstudent.state, STATEID, STATE);
strsub(line, students[*id].ofstudent.zip, ZIPID, ZIP);
students[*id].age = atoi(&line[AGEID]);
students[*id].gpa = atoi(&line[GPAID]);
(*id)++;
}
fclose(data);
}
//sorts struct student array containing num (gpa) elements into
//ascending order
void sortStudentGpa(Student *students, int id) {
int i, j; // indexes into unsorted and sorted partitions
Student temp; // temporarily holds an element from the array
for (i = 1; i < id; ++i) {
temp = students[i];
j = i - 1;
while (j >= 0 && temp.gpa < students[j].gpa) {
students[j + 1] = students[j];
j = j - 1;
}
students[j + 1] = temp;
}
}
void maxGpa(Student *students, int id) {
int iwithmax, i;
float max = 0;
for ( i = 0 ; i < id ; i++) {
if (students -> gpa > max) {
max = students -> gpa;
iwithmax = i;
}
}
printf("\n\nHighest GPA is done by Student %d with GPA = %f", iwithmax, max);
}

Answer 1

In the maxGpa function just change the definition as
void maxGpa(Student *students, int id);
then in the maxGpa function do the following changes
void maxGpa(Student *students, int id) {
int iwithmax, i;
float max = 0;
for ( i = 0 ; i < id ; i++) {
if (students -> gpa > max) {
max = students -> gpa;
iwithmax = i;
}
}
Try this.....