What will be the output of the program?

#include<stdio.h>

int main()
{
    struct s1
    {
        char *z;
    int i;
    struct s1 *p;
    };
    static struct s1 a[] = {{"Nagpur", 1, a+1} , {"Chennai", 2, a+2} , 
                            {"Bangalore", 3, a} };

    struct s1 *ptr = a;
    printf("%s,", ++(ptr->z));
    printf(" %s,", a[(++ptr)->i].z);
    printf(" %s", a[--(ptr->p->i)].z);
    return 0;
}