Linked lists and functions

Question

My program adds a name and age attribute to a list of PERSONS. I'd like to have a function that passes the "first" and "last" pointer to this list. From here, I wanted the program to start from the first pointer and add that age to the next, and the next, until the last pointer is reached.

For example, if my list were:

Jane (36 yrs), Bob (14 yrs), Rachel (10 yrs)

I want it to sum up 36 + 14 + 10 = 60

Please help!

So far, i have the function prototype to be

int total_age(person **f, person **l)
{
   int sum=0;
   person *temp;
   sum = sum + person->age;
}

How do I run through each person.age value for from first to last?

amdixon · Accepted Answer · 2013-12-07 02:55:44Z

1

Since you said this is a linked list, I'm assuming that each Person object has a pointer to the next person in the list. I'll call this Person->next. I'm also assuming that the next value of the last person in the list is NULL.

So then you just need to iterate through the list, adding the age at each node. This just involves creating a while loop (and adding a return statement):

int total_age(person **f, person **l)
{
   int sum = 0;
   person *temp = *f;
   while (temp != NULL)
   {
       sum = sum + temp->age;
       temp = temp->next;
   }
   return sum;
}

Note that you don't actually need the last item in the list to be passed to the function.

edited Dec 7, 2013 at 2:55

amdixon

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answered Dec 7, 2013 at 2:51

seaotternerd

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Comments

jarmod · Accepted Answer · 2013-12-07 02:56:45Z

0

Well, first of all you have to iterate over the linked list elements, for example:

int total_age(person *f)
{
  int sum = 0;

  for (person *p = f; p; p = p->next)
  {
    sum += p->age;
  }

  return sum;
}

If you're not planning to change the first and last pointers, then simply pass pointer to person, not pointer to pointer to person. Also, no need for pointer to last person.

answered Dec 7, 2013 at 2:56

jarmod

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