typedef struct
{
    int day, month, year;
}date;

typedef struct
{
    char name[15];
    date birth;
    int courses;
    int *grades;
}student;

printf("What is the number of students?n");
    scanf("%d", &size); //asking for size from user and creating 'size' number of structs
    for (i = 0; i < size; i++) {
        pData[i] = malloc(sizeof(student) * size);
    }
    ........ //initializing char and birth
    for (i = 0; i < size; i++) {
        printf("nPlease enter number of courses of student #%d:n", i+1);
        scanf("%d", &pData[i]->courses); //allocating memory for array of grades for each student (i)
        pData[i]->grades = (int*)malloc(sizeof(int)*pData[i]->courses);
    }
    for (j = 0; j < size; j++) {
        for (i = 0; i < pData[j]->courses; i++) {
            printf("nPlease enter grades of student #%d in course #%dn", j+1, i+1);
            scanf("%d", &pData[j]->grades[i]);
        } //entering grades of each student

for (i = 0; i < size; i++) {
        free(pData[i].grades);
    }
    free(pData);
    pData = NULL;