Linked lists, how to insert if head does not exist?

Question

I got a linked list, which should save the Outcome (W or L) and the gained/lost points for each match. All good so far, but I'm getting trouble when the head does not exist/is empty. I also realized I have a pretty bad overview of how to implement linked lists, anyone got good and understandable resources? Anyway this is my code:

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

struct node {
  int point;
  char outcome;
  struct node *next;
};

void add(struct node *data){
    if(data == NULL){
    data = malloc(sizeof(struct node));
    printf("Outcome and points?\n");
    int point;
    char outcome;
    scanf("%c %d",&outcome,&point);
    fgetc(stdin);
    data->point=point;
    data->outcome=outcome;
    data->next=NULL;
    }else{
        struct node *current= data;
        while(current->next != NULL){
            current = current->next;
        }
        current->next = malloc(sizeof(struct node));
        current=current->next;
        printf("Outcome and points?\n");
        int point;
        char outcome;
        scanf("%c %d",&outcome,&point);
        fgetc(stdin);
        current->point=point;
        current->outcome=outcome;
        current->next=NULL;
    }

}

void print(struct node *data){
    struct node *current = data;
    while(current != NULL){
        printf("%c with %3d\n",current->outcome,current->point);
        current = current->next;
    }
}

int main()
{
    struct node *head=NULL;     
    add(head); 
    add(head);
    add(head); 
    print(head);
}

Any help would be appreciated :)

Answer 1

When you execute:

void add(struct node *data){
    if(data == NULL){
    data = malloc(sizeof(struct node));

the value of head does not change in the calling function.

Suggest a change of strategy.

struct node* add(struct node *head)
{
   if(head == NULL){
      head = malloc(sizeof(struct node));
      printf("Outcome and points?\n");
      int point;
      char outcome;
      scanf("%c %d",&outcome,&point);
      fgetc(stdin);
      head->point=point;
      head->outcome=outcome;
      head->next=NULL;
   }else{
      struct node *current= head;
      while(current->next != NULL){
         current = current->next;
      }
      current->next = malloc(sizeof(struct node));
      current=current->next;
      printf("Outcome and points?\n");
      int point;
      char outcome;
      scanf("%c %d",&outcome,&point);
      fgetc(stdin);
      current->point=point;
      current->outcome=outcome;
      current->next=NULL;
   }
   return head;
}

And, then change the usage:

int main()
{
    struct node *head = add(NULL);     
    add(head);
    add(head); 
    print(head);
}