Program to understand how a pointer to structure is returned from a function

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
struct student
{
char name[20];
int rollno;
int marks;
};
void display(struct student *);
struct student *func( );
struct student *ptr;
main( )
{
struct student *stuptr;
stuptr = func( );
display(stuptr);
free(stuptr);
}
struct student *func( )
{
ptr = (struct student *) malloc(sizeof(struct student) );
strcpy( ptr->name, "Joseph");
ptr->rollno = 15;
ptr->marks = 98;
return ptr;
}
void display( struct student *stuptr)
{
printf("Name  - %s\t", stuptr->name);
printf("Rollno  - %d\t", stuptr->rollno);
printf("Marks  - %d\n", stuptr->marks);
}