Program in c that generates random characters and insert them in a linked list

This program should generate n*2 random characters and insert them into a linked list. The problem is that, even if random characters are generated, the linked list is composed by numbers, I can't understand why. Thanks for helping.

    struct node{
        char *string;
       struct node *next;
   };


   void display(struct node *head){
       struct node *tmp;
       tmp = head;

        while(tmp!=NULL){
            printf("%d\t", tmp->string);
            tmp = tmp->next;

        }
   }
    struct node* front(struct node *head, char c) {
        struct node *p;
        p = malloc(sizeof(struct node));
        p->string = c;
        p->next = head;
        return(p);
    };

   int main() {
       struct node *l;
       int n, i, op;
       char c;

       do{
        printf("digit an integer >1: ");
        scanf("%d",&n);
        if(n<1){
          printf("the integer must be >1: ");
       }
       }while(n<1);

        l = malloc(sizeof(struct node));
        l = NULL;

        for(i=0;i<(2*n); i++) {
        char c = 'A' + (rand() % (126 - (33) + 1) - (-1));
        l = front(l, c);
    };
     display(l);
     return 0;
    };