Pointer arrays and structures
 

Hey all, I am a C beginner. My problem with my code is that I get a segfault.
Here's my code

#include <stdio.h>



struct studentInfo {

    int totalClasses;

    float GPA;

    char studentName[41];

};





main()

{

    int numOfStudents, i;

    printf("How many students would you like to take account of? ");

    scanf(" %d", &numOfStudents);



    struct studentInfo *students[numOfStudents-1];



    for (i=0; i < numOfStudents; i++)

    {

        printf("Enter the total number of the student's classes: ");

        scanf(" %d", &students[i]->totalClasses);



        printf("Enter the student's GPA: ");

        scanf(" %f", &students[i]->GPA);

        getchar();  /* Clear the extra keypress in the buffer */



        printf("Enter the student's name: ");

        fgets(students[i]->studentName, 41, stdin);

        printf("\n\n");





    }



    printf("\n\n");



    for (i=0; i < numOfStudents; i++)

    {

        printf("Student Name: %s", students[i]->studentName);

        printf("Student GPA: %.3f\n", students[i]->GPA);

        printf("Number of Student Classes: %d\n\n", students[i]->totalClasses);

    }

    printf("\n\n");



    printf("Goodbye.\n");



    return 0;

}

According to gdb the segfault happens on:

        scanf(" %d", &students[i]->totalClasses);

But I don't know what I am doing wrong. Any help?

Re: Pointer arrays and structures
 

You have allocated space for all of the studentInfo pointers here (except the last one, you should not be subtracting 1):

struct studentInfo *students[numOfStudents-1];

But, you have not allocated space for the actual studentInfo structures that each pointer will point to. To do that you will have to make a loop that allocates a studentInfo for each pointer using malloc().

Something like:

students[i] = (studentInfo*) malloc( sizeof(studentInfo) );

Re: Pointer arrays and structures
 

Ahh! I see, so you need to allocate space for each structure that the pointer points to.

I ended up using:

        students[i] = (struct studentInfo *)malloc(sizeof(struct studentInfo));

And now everything works fine. Thank you. :)