I'm learning dynamic memory allocation and using doubly linked lists right now, and am not really understanding any of it. I want to keep a list of persons (which also has to be alphabetically sorted but I feel like that's still far away for me), but with using malloc and stuff.

struct person 
{
char name;
char adress;
int phone number; 
};

From main I'll access a func newPerson.

1. Question: Now that I can't use an array struct person persons[50] anymore, how do I add a new person to my list? And what does my fgets line look like? Because fgets(persons['currentPosition'].name, 50, stdin) doesn't seem to be working

That's all for now, I've forgotten my other question...

CodePudding user response：

In order to add another person to your list, you need to do this way:

person * myperson = (person *) malloc(sizeof(person));

CodePudding user response：

I am using a linked list as an example but the process is the same for a double linked list.

#include <stdio.h>
#include <stdlib.h>

typedef struct list_node {
    void* value;
    struct list_node* next;
} list_node;

typedef struct person {
    char* name;
} person;

int main(void) {
    list_node* list = malloc(sizeof(*list));
    list->next = NULL;

    person* mike = malloc(sizeof(*mike));

    mike->name = malloc(20*sizeof(char));
    fgets(mike->name ,20 ,stdin);

    list->value = mike;

    printf(" Name : %s " ,((person*)list->value)->name);
    return 0;
}

You have to allocate memory for the person and then you have to allocate memory again for the person's name otherwise you will get segmentation fault.