CODEWITHSUNDEEP
cstruct
Josephine
Josephine

Reputation: 261

Structures within structures?

I'm writing a database of students in C and I've defined two structures Student and Course which look like this:

typedef struct student Student;
typedef struct course Course;

struct course
{
    char number[300];
    char title[300];
    char instructor[300];
    char days[10];
    char start[10];
    char end[10];
    char location[300];
};

struct student 
{
    char name[300];
    int age;
    Course course1;
    Course course2;
};

Student *Data[30];
Course *Courses[30];

I'm having trouble displaying the students I create though. I just want to print out the name, age and two courses, but I'm having trouble accessing the elements of the course structure through the student one.

I've tried this:

printf("course1: %s\t%-40s%-30s\t%s\t%s-%s\t%s\n",
       Data[i]->course1.number,
       Data[i]->course1.title,
       Data[i]->course1.instructor,
       Data[i]->course1.days,
       Data[i]->course1.start,
       Data[i]->course1.end,
       Data[i]->course1.location);

But of course that isn't working...

Upvotes: 2

Views: 222

Answers (1)

Java42
Java42

Reputation: 7716

I've simplified your structs a bit as an instructional example. This might help you to understand how to access the data. Tweak/expand as necessary to suit your needs.

typedef struct student Student;
typedef struct course Course;

struct course {
    char title[300];
};

struct student {
    char name[300];
    Course * course;  // pointer to a course
};

Student students[30]; // preallocate 30 students
Course  courses[30];  // preallocate 30 courses

Tester:

void main(void) {

    // 1st course
    strcpy(courses[0].title,"C Language 101");

    // 1st Student
    strcpy(students[0].name,"Charles");

    // Assign 1st Student to course #1
    students[0].course = & courses[0];

    printf("Student 1: name=%s course=%s", students[0].name, students[0].course->title);

    return;
}

Output:

Student 1: name=Charles course=C Language 101

Upvotes: 2

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