How to find the difference between time of 2 clocks using structure?

CODE

How to find the difference between time of 2 clocks using structure?

//Write a program to find the difference between time of 2 clocks using structure…

struct diff

{

    int hour,min,sec;

};

int main()

{

    struct diff c1,c2,*p1,*p2;

    p1=&c1;

    p2=&c2;

    void sub(struct diff *p1,struct diff *p2);

    sub(&c1,&c2);

}

void sub(struct diff *p1,struct diff *p2)

{

    struct diff difference;

    printf("\n enter time at first clock(hour:minute:second):");

    scanf("%d%d%d",&p1->hour,&p1->min,&p1->sec);

    printf("\n enter time at second clock(hour:minute:second):");

    scanf("%d%d%d",&p2->hour,&p2->min,&p2->sec);

    difference.hour=abs( p1->hour - p2->hour);

    difference.min=abs(p1->min-p2->min);

    difference.sec=abs(p1->sec-p2->sec);

    printf("\n difference= %d hours %d min %d sec",difference.hour,difference.min,difference.sec);

}

Output:

enter time at first clock(hour:minute:second):48

23

79

 enter time at second clock(hour:minute:second):15

76

62

 difference= 33 hours 53 min 17 sec